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The Obesity Code: Unlocking the Secrets of Weight Loss

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Everything you believe about how to lose weight is wrong. Weight gain and obesity are driven by hormones—in everyone—and only by understanding the effects of insulin and insulin resistance can we achieve lasting weight loss.

In this highly readable and provocative book, Dr. Jason Fung sets out an original, robust theory of obesity that provides startling insights into proper nutrition. In addition to his five basic steps, a set of lifelong habits that will improve your health and control your insulin levels, Dr. Fung explains how to use intermittent fasting to break the cycle of insulin resistance and reach a healthy weight—for good.

315 pages, Paperback

First published March 3, 2016

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Jason Fung

75 books1,325 followers

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Displaying 1 - 30 of 3,283 reviews
Profile Image for Chris Bartos.
4 reviews6 followers
October 12, 2016
The best diet book ever!

I've read more diet books than I know what to do with here is why this book is the best:
1. It explains why calorie restriction doesn't work.
2. It explains why over eating doesn't cause you to gain weight.
3. It explains in simple terms why we get fat.
4. It's a whole lifestyle approach to losing weight.
5. It doesn't tell you one diet is better than another, but it tells you exactly why most diets work but for only about 6 months.
6. Then, it tells you what to do to avoid plateauing after 6 months.
7. If you think being a "vegan" is far healthier than "Paleo" or vice versa, you can read this book without getting angry.
8. The guidelines are simple to follow.

I recommend this book for anybody who wants to understand weight gain / weight loss. This is probably the only diet book you'll ever need!
Profile Image for Otis Chandler.
388 reviews113k followers
February 25, 2019
The best book about how to eat healthy and the reasoning behind it that I've yet read. Well backed with science and uses studies to make all his points. Highly recommended for everyone (the title is misleading, its not just for obese people).

The main theory of the book is that the root cause of obesity and weight gain is a complex hormonal imbalance, that stems from high blood insulin levels. High insulin levels are responsible for obesity, and to a smaller degree, so can high cortisol levels (being overly stressed can lead to weight gain). High insulin levels are a direct result of poor diet, and are 95% of the cause of obesity. Exercise is 5% of it (I would have said it was 70/30, so this was interesting). The foods that contribute to weight gain are largely a result of too much sugar and too much refined carbohydrates. Obesity can also be "genetic" and passed to kids in the sense that if a mother has high insulin levels it will be passed to the child.

A fascinating part of the book was that while many of us would intuitively say sugar and processed carbs are the culprit, the prevailing wisdom by all official sources is different - eg look at what the NHS website says: "Obesity is generally caused by eating too much and moving too little.". This theory of calories in minus calories out, has prevailed for 50+ years, and the book makes a good case for it being wrong. The kind of calories make all the difference. To prove this, the book goes into all the data it could find about weight loss studies done, and found that generally, diets don't work. Shocker, I know, because again intuitively we all know that - its easy to go on a diet and lose weight, but then it always comes back. Why is this?

"Losing weight triggers two important responses. First, total energy expenditure is immediately and indefinitely reduced in order to conserve the available energy. Second, hormonal hunger signaling is immediately and indefinitely amplified in an effort to acquire more food. Weight loss results in increased hunger and decreased metabolism. This evolutionary survival strategy has a single purpose: to make us regain the lost weight."

Basically, our bodies are like thermostats in our houses - they are set to a certain weight, and our bodies do their darnedest to keep our weight there. To change our weight, we have to change our "body set weight" first. To do that, we have to lower our insulin levels, by eating less things that make them spike.

This book was recommended to me by my doctor, as I did some bloodwork which said I high slightly high cholesterol and should lose 10 pounds. He recommended I start doing 8/16 fasting, and when I asked for reading material to learn about it, he recommended this book. I can report after 2 months, it really works. I don't miss breakfast - I just have coffee on many mornings, and am fine - and lost the 10 pounds! The reason fasting works is well described in the book, and its a huge new tool in my arsenal. Basically, our bodies need time to process insulin in our bodies, and if we don't get it, it leads to continuous elevated insulin levels, which leads to weight gain. So by not eating for 12 hours a day (overnight), or 16 hours (overnight plus skip breakfast), you can lower your insulin levels. This is a neat trick as now I know if I have a huge dinner, its not necessary to have breakfast. It's also helpful as snacking, in particular late night snacking, is one of the worst things for you. In fact:

"It is simply not necessary to eat the minute we wake up. We imagine the need to “fuel up” for the day ahead. However, our body has already done that automatically. Every morning, just before we wake up, a natural circadian rhythm jolts our bodies with a heady mix of growth hormone, cortisol, epinephrine and norepinephrine (adrenalin). This cocktail stimulates the liver to make new glucose, essentially giving us a shot of the good stuff to wake us up. This effect is called the dawn phenomenon, and it has been well described for decades.


breakfast needs to be downgraded from “most important meal of the day” to “meal.” Different nations have different breakfast traditions. The big “American” breakfast contrasts directly with the French “petit dejeuner” or “small lunch.” The key word here is “small.”

Fasting may sound like a terrible hungry hangover, but it's actually very natural and a part of our human history. It's also a very effective weight loss tool:

"Regular fasting, by routinely lowering insulin levels, has been shown to significantly improve insulin sensitivity. This finding is the missing piece in the weight-loss puzzle. Most diets restrict the intake of foods that cause increased insulin secretion, but don’t address insulin resistance. You lose weight initially, but insulin resistance keeps your insulin levels and body set weight high. By fasting, you can efficiently reduce your body’s insulin resistance, since it requires both persistent and high levels."

The reason that most of us don't know how to eat well? Because nobody really knows the truth, because the food industry has spent money to conceal it, being subsidized by the government all along. The book Salt Sugar Fat goes into more depth on this topic, but with such big dollars at stake you couldn't exactly declare that everything that Nestle or Proctor & Gamble makes is bad for you (it is). Their first scapegoat was fats, and thus was born several decades of focus on "low fat foods" - however, there are no studies that actually find a correlation between low fat diets and lower cholesterol and thus reduced heart disease. It just didn't exist - the whole "low fat" diet thing failed. Now there is another scapegoat:

"But the obesity epidemic couldn’t very well be ignored, and a culprit had to be found. “Calories” was the perfect scapegoat. Eat fewer calories, they said. But eat more of everything else. There is no company that sells “Calories,” nor is there a brand called “Calories.” There is no food called “Calories.” Nameless and faceless, calories were the ideal stooge. “Calories” could now take all the blame."

Soda and all sugary drinks deserve a large portion of the blame. The data of the rise of soda and obesity are strongly correlated, and happened over the same years. If you are still drinking soda or any drink other than water or sparkling water, stop!

"DURING THE YEARS 1977 to 2000, the prevalence of childhood obesity skyrocketed in every age category. Obesity in children aged six to eleven increased from 7 percent to 15.3 percent. For children aged twelve to nineteen, it more than tripled, from 5 percent to 15.5 percent."

But then a good thing happened, and in the 21st century in the US we started to recognize the evils of soda and drink less. Profits for Coca Cola fell. So then:

But the sugar pushers weren’t so easily defeated. Knowing that they were fighting a losing battle in much of North America and Europe, they took aim at Asia to make up for lost profits. Asian sugar consumption is rising at almost 5 percent per year, 3 even as it has stabilized or fallen in North America. The result has been a diabetes catastrophe. In 2013, an estimated 11.6 percent of Chinese adults have type 2 diabetes, eclipsing even the long-time champion: the U.S., at 11.3 percent.

So far I've only talked about avoid sugar and processed carbohydrates generally - but the book does a great job of better explaining why processed carbohydrates are so bad. Basically, the processing removes all the "good stuff" they come with that offset the effects of the carbs.

"refining encourages overconsumption. For example, making a glass of orange juice may require four or five oranges. It is very easy to drink a glass of juice, but eating five oranges is not so easy. By removing everything other than the carbohydrate, we tend to overconsume what is left. If we had to eat all the fiber and bulk associated with five oranges, we might think twice about it. The same applies to grains and vegetables."

And for grains:

"Processing methods have changed significantly over the centuries. Wheat berries were traditionally ground by large millstones powered by animals or humans. The modern flourmill has replaced traditional stone grinding. The bran, middlings, germ and oils are efficiently and completely removed, leaving the pure white starch. Most of the vitamins, proteins, fiber and fats are removed along with the outer hull and bran. The flour is ground to such a fine dust that its absorption by the intestine is extremely rapid. The increased rate of glucose absorption amplifies the insulin effect. Whole wheat and whole grain flours retain some of the bran and germ, but suffer from the same problem of rapid absorption."

Side question to anyone reading this: does anyone have a good source of really healthy whole wheat bread? We eat Dave's bread currently.

So what should you eat? The book concludes with a chapter on this topic, basically concluding:

"THERE ARE FIVE basic steps in weight loss: Reduce your consumption of added sugars. Reduced your consumption of refined grains. Moderate your protein intake. Increase your consumption of natural fats. Increase your consumption of fiber and vinegar."

Other good tidbits on eating:
* Vinegar can help offset insulin, so eating it with bread, chips, etc is a good idea.
* Dark chocolate is surprisingly healthy and low in sugar (not so for milk chocolate).
* Nuts are especially healthy for you, especially pistachios. Nuts are already my snack of choice at 5pm.
* Red wine has little impact on insulin levels (yay!)
* Coffee is good for you! So is tea!
* Really try to avoid refined grains like white flour. That means bread, bagels, English muffins, roti, naan breads, dinner rolls, bread sticks, Melba toasts, crackers, tea biscuits, scones, tortillas, wraps, muffins, cookies, cakes, cupcakes, donuts, and more.
* Quinoa and beans are really good for you.
* Natural fats are really good for you - things like olive oil, butter, avocados. Avoid processed oils like vegetable oils.
Profile Image for Negin.
608 reviews151 followers
June 20, 2018
This is a fabulous book, probably the best diet/health book that I’ve ever read. I’ve been meaning to read this for a while, but there was a bit of a dread factor. Honestly, I’ve read so many diet and health books through the years, that I needed yet another one like I need a drill through my head. I thought that this would be boring and that I would simply skip to the part where he tells us what to do. I was pleasantly surprised that I didn’t find it boring at all. It was written clearly and organized in a very user-friendly way. Finally, a book with advice that makes sense!

My favorite quotes (and there are far too many to list here):
“A recent study suggests that 75 per cent of the weight-loss response in obesity is predicted by insulin levels. Not willpower. Not caloric intake. Not peer support or peer pressure. Not exercise. Just insulin.”

“Diets work well at the start, but as we lose weight, our metabolism slows.”

“The reason diets are so hard and often unsuccessful is that we are constantly fighting our own body. As we lose weight, our body tries to bring it back up.”

UPDATE: It has been over a year since I read this and I have tried to follow this program. Although I rated this book 5 Stars at the time, I would probably give it a slightly lower rating now. If you are interested in following this program completely, or in reading his other book, you may be interested in reading my review for that one. There are parts of intermittent fasting that I agree with, but on the whole, it's not something that has worked for me, and not something that I can recommend.
Profile Image for Theresa Alan.
Author 10 books1,012 followers
May 1, 2019
“Diets work well at the start, but as we lose weight, our metabolism slows. Compensatory mechanisms start almost immediately and persist almost indefinitely.”

This book challenges many of the things I was taught growing up about weight, nutrition, and health. I was a teenager in the late 80s, a time well before we had any activism in regards to fat shaming. At that time, if you were overweight, it was because you were a bad person—slothful, gluttonous, lazy. I was taught that fat in food is evil, so, like many people, I was endlessly on a low-fat diet and afraid of oils and butter. As I got older, I learned that olive oil is much better for you than other oils. The key to most things we eat isn’t the food itself but how it gets processed. I don’t love to cook, but if I’m going to lose and maintain a healthy weight, I can’t be so lazy as to rely on prepacked microwavable foods, even organic vegetarian stuff.

Dr. Fung really downplays exercise in terms of weight loss but agrees that it helps with stress reduction and mood. I have a hard time believing that exercise doesn’t have much to do with weight loss. I know that the foods and beverages we consume are far more important than exercise, but when I first quit my day job and went freelance, I lost fifteen pounds without trying. I was thirty-three years old and down to my high school weight. In high school, I was dancing two hours a day. The only change I made as an adult is that, without have an eight-to-five job, I was able to walk for 45 minutes a day in addition to my normal workouts three or four days a week. That little bit of extra exercise made the difference.

The improved mood aspect of exercise is vital. Dr. Fung talks about the importance of getting a good night’s sleep and how even one night of sleep deprivation causes havoc with the two most important aspects of weight loss: insulin and cortisol. I’m not a great sleeper and envy people who can manage eight decent hours of sleep. Exercise does help me in that regard.

He also suggests fasting for periods of 24 to 36 hours. I get extraordinarily cranky if I go more than five or six hours during the day without eating, so I’ll just fast at night—no more late-night snacking, even on something as innocuous as an apple. I do appreciate his advice not to snack. It makes sense, but then some sources have been telling me to eat five or six small meals a day. Fung points out that companies make money when we eat, not when we don’t eat.

I also appreciate his point that diets should be mixed up. He writes that the average American gains one or two pounds a year, which doesn’t sound like much, but obviously adds up after twenty years. Particularly if you’re a short female like myself. If I put on five pounds, it is very noticeable in a way it wouldn’t be on a 6’2” male. I do know that exercise routines need to be mixed up at least every six weeks because our bodies grow used to whatever we’re doing.

Because of this book I feel much better about my coffee drinking habits and will get through my fear of fat and eat more nuts. I do eat avocado already, but the lingering fear of the fat will not be easily shaken.

I recommend this book. It’s thought provoking and illuminating.

For more reviews, please visit http://www.theresaalan.net/blog
Profile Image for Andy.
1,373 reviews464 followers
January 23, 2022
Dr. Fung does a nice job critiquing the nonsense we were all taught for 50 years about calories and cholesterol, etc.
Unfortunately, he seems to have hoisted himself on his own petard. He lambastes others for recommending things that are not evidence-based, but then his big advice is to fast, whereas the evidence indicates that fasting doesn't work any better than calorie restriction: " Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction."http://jamanetwork.com/journals/jamai...

It's a shame Fung went out on a limb like that, because he does explain things clearly. As it stands, I would have to say the following books on the same topic are better overall depending on the audience.
Why We Get Fat: And What to Do About It
Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease
Fat Chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease
Eat Bacon, Don't Jog: A Contrarian's Guide to Diet, Exercise, and What Actually Works

Why We Get Fat And What to Do About It by Gary Taubes
Fat Chance Beating the Odds Against Sugar, Processed Food, Obesity, and Disease by Robert H. Lustig
Eat Bacon, Don't Jog A Contrarian's Guide to Diet, Exercise, and What Actually Works by Grant Petersen

Nerd addendum:
For help with consulting original medical research papers:
Evidence-Based Medicine: How to Practice and Teach EBM
Profile Image for Christy.
3,809 reviews32.3k followers
May 9, 2018
The Obesity Code is the 5th book in my non-fiction challenge for 2018. This book was very informative and interesting. It focused on insulin resistance being the trigger for those who struggle with weight loss- more in the long term than short term. It also touched on fasting and intermittent fasting and the pluses of that. Overall, it was an informative read.
Profile Image for Stephanie *Eff your feelings*.
239 reviews1,193 followers
January 22, 2018
Don’t let the title of this book put you off, it’s not a diet book. I typically don’t read diet books because diets are pointless.... we all know that.

More precisely (as pointed out in the book), all diets work at first and then one plateaus and then the weight comes back. On top of that, now you’ve lowered your metabolism because you pissed off your body, because it was perfectly happy at the weight it was, so it increased your hunger and lowered your metabolism to get back to it’s happy place and then some. Now you do the whole diet game once again....reduce calories, reduce carbs, reduce, reduce, reduce and so, your metabolism is reduced once again. Fun fact: your metabolism never really recovers. So each time you do this to your body, it’s even harder to lose weight the next time.....and you’re hungrier. That explains why out diet and exercise obsessed culture is still fat.

Then you feel like a big fat failure. And now your depressed, so you eat comfort food to make yourself feel better. The cycle is endless.

What can you do?

Read the book for the full story (it’s well worth the read), but what makes you fat is insulin. Weight gain is hormonal. We eat too often and when you do that, your insulin level remains too high all the time. When your insulin is too high, you become insulin resistant and that’s bad. Grazing, eating six or more small meals a day is horrible for you. Snacking is horrible for you. Eat your meals and be done with it. Leave at least 14 hours between your last meal of the day to when you break your fast the next day.

Of course, eating healthy and avoiding the evil processed foods are important.

"THERE ARE FIVE basic steps in weight loss:
Reduce your consumption of added sugars.
Reduced your consumption of refined grains.
Moderate your protein intake.
Increase your consumption of natural fats.
Increase your consumption of fiber and vinegar."

Also, you have to fast to bring your insulin levels back in line. Not consuming calories for a day every so often won’t kill you. I’ve done before and I’m still here.... typing this.

This book is an easy read and makes complete sense. Basically, in the end, we all knew what to do... it’s not all that complicated. It may not always be easy, but it’s complicated. I highly recommend it.
Profile Image for Angela Boord.
Author 8 books89 followers
February 7, 2017
I'm not at all sure how to rate this book. Overall, I think his argument that chronically high insulin levels cause obesity is probably true. But there are some logical gymnastics involved in this book, too. There was a lot of assertion that "calories don't matter" and "calories in/calories out" is wrong. But getting rid of snacks, as Fung suggests, will, for most people, automatically reduce calories. Replacing a piece of white bread and butter at dinner with steamed broccoli? Lower calories. Fasting 3 days a week without eating more on the other days? Lower calories. Cutting out sodas? Definitely less calories! So do calories have anything to do with losing weight or not? Although he continually asserts that they do not, it certainly seems that they must.

Also, it bugs me that diet books - this one included - toss out the possibility that there could be any difference between women and men dieting offhandedly, in the matter of a couple of paragraphs. But there is a big biological difference between women and men, and that is that women have babies. How does fasting affect fertility? What about postpartum women who want to take off baby weight while still maintaining a decent milk supply? What about us? Nobody wants to tackle this issue apparently, or all diet authors assume it just doesn't exist.

But in the end, as a practicing Catholic, the idea that fasting might be an integral piece of a healthy life does make some sense.
Profile Image for Cindy Rollins.
Author 22 books2,015 followers
August 6, 2017
I know a lot about dieting having done it for most of my life. I know that calorie counting does lead to yo-yo weight management and yet it is often the only option. Recently, I lost 25 lbs going back to Weight Watchers and now I am in the inevitable plateau with a few pounds creeping back up. This book was long, drawn out, and logical. If it hadn't been I might have rejected the ideas Dr. Fung promoted, especially the idea of intermittent fasting, something I have not been willing to think about until lately. I appreciated the way this book brought together so many different options. It made me really see that it must be a lifestyle change, but that can only happen under certain circumstances. It can't be a lifestyle of constantly fighting against yourself. Now comes the real test of the book. Can I do it? We had a wedding this weekend with another one coming up in November. I am going to try intermittent fasting until then. If I can't do it and I can't break this plateau, I will lower my review stars. If I can I will come back and give it 5 stars.

The best thing about this book is it took what I already knew by experience and put it into a context which gave me hope.
Profile Image for Phil Sykora.
195 reviews67 followers
June 24, 2020
At 160lbs, I'm a competitive powerlifter who can squat 400lbs, deadlift 500lbs, and bench 270lbs. My sport often requires periods of bulking and cutting (although not to bodybuilder levels; you still have to maintain some fat to move weight). I like to think I know a thing or two about what actually works when it comes to losing weight -- not what optimally works, but what actually works.

I’m saying this to call attention to the fact that I put a borderline-narcissist level of attention into my body and yet I wouldn’t even diet like Dr. Fung recommends.

The Obesity Code starts off really well.

"Calories in, calories out" is often terrible advice because it neglects the fact that different foods break down differently in the body. Some give you more energy and some give you less. 150 calories of Oreos isn't the same as 150 calories of oatmeal -- not in terms of volume, effect on satiety, or effect on energy levels. You should stay away from highly processed foods and refined sugar except on special occasions. Insulin is a main driver of obesity, and insulin is highly affected by refined sugar, so in order to reduce your bodyfat levels long-term, you need to lower your insulin levels.

He even admits that obesity is a wildly complicated problem that we've approached with all manners of advice that might be inappropriate for your particular situation. I particularly like this passage, until… well, you’ll see:

When it comes to the question of what to eat, you pretty much already knew the answer. Most diets conspicuously resemble each other. There is far more agreement than discord. Eliminate sugars and refined grains. Eat more fiber. Eat vegetables. Eat organic. Eat more home-cooked meals. Avoid fast food. Eat whole unprocessed foods. Avoid artificial colors and flavors. Avoid processed or microwavable foods. Whether you follow low carb, low calories, South Beach, Atkins, or some other mainstream diet, the advice is very similar. Sure, there are particular nuances to each diet, particularly with respect to dietary fats, but they tend to agree more than they disagree…

All diets work in the short term. But we’ve been ignored the longterm problem of insulin resistance. There is one more piece of the puzzle--a solution found centuries ago. A practice that has been enshrined in the nutritional lore of virtually every population on earth...






Because everyone's favorite fad diet right now is "intermittent fasting," and that's what Dr. Fung recommends. Most of the time, when people talk about intermittent fasting, it isn't really intermittent fasting but daily time-restricted feeding, first coined by Martin Berkhan and stolen by Greg O'Gallagher of Kinobody. You set up a period of 8 hours in the day when you're allowed to eat, usually 10AM-6PM or so, and you stick to it. It's really just a fancier way of saying "skip breakfast." It's pretty approachable for most people, although some still struggle.

What isn't approachable are entire days of not eating anything, or alternate day fasting. Food is an integral part of most people's social lives and daily routines. Cutting it out entirely just to lose a few pounds is a recipe doomed to fail. In fact, for reasons that I think should be head-smackingly obvious, this type of intermittent fasting is arguably the hardest diet to maintain over the long term, which is only my second biggest issue with it.

Compared to the general population, I'm very dedicated -- probably more dedicated than at least 70% of the people reading this review, even if I can't get those lower abs to pop -- and I would never even think to go 48 or 72 hours without any food on a regular basis, because, well, it sounds awful. It would be too much effort for too little impact, and I think that's true for most of you, as well. The average person makes it about 9 hours without eating. Don’t quickly jump to 72.

You just want to get a little bit fitter. You want to lose fat, feel better, and look better on the beach. If that sounds like you, 48 hour fasts are not the way to go. They're a quick ticket to crash dieting.

If, instead, like a lot of the people who come to Dr. Fung's clinic, you've been struggling with Type 2 diabetes for years -- maybe decades -- and you've been trying every diet intervention under the sun with little to show for it and now you have to make a serious change or you're at risk of losing a limb, this book is definitely for you. Because Dr. Fung knows exactly what you need: an extreme intervention for the extremely motivated.

But most people aren't that highly motivated (and, as we'll see, the research bares that out). I am not that highly motivated, even though I've tried this type of fasting before (and if any of you powerlifting nerds have ever tried to do 10 sets of 3 ATG squats with 80% of your 1rm after a full day of fasting, you'd know how unnecessarily difficult it is when you could've just, you know, ate a couple eggs before breakfast).

In a short list, here are my main problems with The Obesity Code:

1. ZERO mention of eating disorders (or, nowadays, "disordered eating").

This is the biggest one because it's the most dangerous.

Dr. Fung regularly recommends “skipping meals” as a way to lose weight, but that’s exactly how a lot of people develop binge eating disorder. That’s particularly true for people with elevated insulin levels and unhealthy eating habits.

To make matter worse, for anyone with binge eating disorder (which, according to the National Institute of Diabetes, is roughly 3.5% of American women and 2% of American men -- but I’d wager those percentages increase five-fold if you’re looking at a population willing to read a book called The Obesity Code), fasting is the worst thing you can do for your body and mental health.

So, if you’ve tried fasting but you find yourself getting so hungry that you just can’t stop yourself from eating, you consume whole boxes of cereal and ice cream, I want you to keep this in mind: it’s okay. Binge eating is part of the human condition. That’s exactly why the body developed the way that it did; fat acts as a storage mechanism for energy in the event that you don’t have anything to eat. Primitive humans alternated between periods of fasting, when they had nothing at all, and feasting, when they made a big kill or found a bunch of food. It’s normal, it’s okay.

Dr. Fung, however, expects you never to have this problem, which is short-sighted and, if your previous food environment encouraged you to overeat, dangerous. When you open a bag of Frito-Lay’s, it isn’t you versus the lure of potato chips, it’s you versus the ingenuity of hundreds of whip-smart food scientists. You’re gonna lose.

So don’t beat yourself up. Ask yourself, “how can I avoid this outcome?” What steps led to your downfall? It’s probably multifactorial, like all obesity. It happened because you had junk food within arm’s reach. It happened because you didn't get enough sleep. It happened because the food itself is engineered to produce that outcome. And, most importantly, it happened because you have elevated cortisol levels as a result of not eating for days at a time.

For reference's sake, the only time the word "binge" pops up in The Obesity Code is on page 315, when Dr. Fung astutely recommends:

Don't binge. After fasting, pretend it never happened. Eat normally, as if you had never fasted.

2. Adherence

Let’s let Dr. Greger of NutritionFacts.org explain this one.

The gist of that research review is that, believe it or not, fasting is really hard.

It gets easier over time because you get used to the elevated cortisol levels and constant hunger, but that doesn’t change the fact that, as far as longterm adherence goes, even though it’s the best way to reduce insulin levels, it’s the hardest intervention to consistently replicate.

Again, it’s the difference between what optimally works, and what actually works.

So what actually works? Starting small and building from there. You might find fasting is PERFECT for you, but don’t pressure yourself to start with 3-day long fasts. It isn’t an overnight cure. Start with daily time-restricted feeding. Skip breakfast. See what happens to your hunger levels. Adjust.

If you ever mess up, ask yourself, “What factors led to my downfall?” It’s NEVER a character problem, it’s just a design problem. Keep playing around.

Also, stop buying the junk. Just stop buying it. If you buy it, you’re gonna eat it. Just stop. Save yourself money. If you binge, binge on apples and peanut butter, not ice cream and oreos. It will still be WAY better for you.

Finally, keep in mind that weight loss is difficult. Even the 10-15lb jumps I make for powerlifting, after I’ve done it for the better part of a decade, are still hard. Focus more on how you feel -- doing things that are common sense like eating whole foods, tracking your intake, and exercising -- and your bodyweight and bodyfat will stabilize over time.
Profile Image for Heather K (dentist in my spare time).
3,857 reviews5,630 followers
March 3, 2020

I've read many, many books on weight loss and dieting over the years, mostly to try to get healthier and in order to understand my body better because I'm a science geek. This book outshines them all.

It takes a lot convincing to change your mindset from the ingrained "calories in, calories out," but Dr. Fung is very compelling. Listening to his book changed my whole mindset about food, sugar, and fake sugar (which is my true weakness). It was truly life changing.

An excellent book with lots of science to back it up. You'll never look at food the same way again.

Profile Image for Canadian Reader.
1,064 reviews23 followers
December 2, 2017
Unfortunately saddled with a poor title, The Obesity Code is not shilling some new fad diet or weight-loss program. In fact, this reader friendly, direct, and humorous book addresses the very serious problems with insulin resistance that so many who eat a western diet high in refined grains (and sugar) are plagued with. A trained nephrologist, Jason Fung has extensive knowledge based on years of experience with patients whose kidney failure and obesity were brought on by Type 2 diabetes. Obesity and insulin regulation problems are, he says, decades in the making. Therefore Fung’s book isn’t just one for fat people or diabetics; it is a book with genuine relevance for those of us who have been blithely and ignorantly eating a diet that slowly (sometimes even rapidly) compromises our health.

We’ve all been taught that a calorie is a calorie and fats are evil. The fact is: the body processes the three main macronutrients in very different ways, and healthy fats do not cause increases in insulin levels that can lead to Type 2 diabetes. Fats also trigger satiety hormones, which carbohydrates don’t do—so a person will actually eat less with fats in the diet. Fung clearly explains the different ways in which carbohydrates, proteins, and fats are broken down by the body. He highlights the particular damage that fructose (seemingly a “safe” sugar because of its low glycemic index) poses to the liver, the only organ that can process it. Fung advocates for fasting as a way to health, to break the insulin resistance cycle, and he tells readers how to do this.

Dr. Fung also keeps a lively and informative blog.
Profile Image for Alice.
229 reviews44 followers
January 12, 2018
So this review covers like 2/3 of the book. I'm getting kinda lazy at the end here. I got bored so I skimmed the actual weight loss advice at the end. This book is probably the best non-fiction I've read so far. The first 2/3 of the book is mostly about things you shouldn't do to lose weight / weight loss myths and it's like reading plot twist after plot twist because it's all bad news. If you are actually reading this to lose weight the last 1/3 explains how to do it. (Which is by fasting.) Fun book.


"Insulin, not calories, causes weight gain. It’s not (and never was) a matter of restricting calories. It’s a matter of reducing insulin."

All foods, not just carbohydrates, stimulate insulin. Thus, all foods can cause weight gain. (It's because of incretins secreted in the stomach and small intestines which increase insulin.)

Also because all foods stimulate insulin, more calories usually equal more insulin because you eat more so calories don't directly cause weight gain, but it's related though the increasing amount of insulin you are getting with more food (calories). (That's the conclusion I came to from reading this.)

1. Cut back sugars and starchy foods. 2. No snacking.
Of the sugars----> specifically Fructose is bad. Also Sucrose if really bad too.

DO NOT EAT MANY SMALL MEALS IN A DAY TO LOSE WEIGHT (Will keep your insulin level elevated for a long period of time with no cool down leading to insulin resistance).
EATING BREAKFAST DOES NOT HELP YOU LOSE WEIGHT. (Only eat breakfast when you are actually hungry.)

"If you want to avoid weight gain, remove all added sugars from your diet. Don’t replace them with artificial sweeteners—as we’ll see in the next chapter, those are equally bad." (I thought everyone knew artificial sweeteners were stupid, but I'm just putting this here for people reading.) It's because artificial sweeteners still raise insulin (which is the real thing causing weight gain). Artificial sweeteners also increase cravings because it senses sweetness without calories causing overcompensation with increased appetite and cravings.

Ok I'm taking notes on this book because I know I'm not going to remember later. I'm going to keep adding until I'm done. Also I skipped the intro because who cares.

"70% of your tendency to gain weight is determined by your parentage. Obesity is overwhelmingly inherited."

"Caloric intake and expenditure are intimately dependent variables. Decreasing Calories In triggers a decrease in Calories Out. A 30 percent reduction in caloric intake results in a 30 percent decrease in caloric expenditure. The end result is minimal weight loss."
(Reducing calories does not help you lose weight because then your body will just use less calories instead.)

Reducing calories does not work because your Metabolism Lowers as your Calorie intake Lowers.
Vise versa for: (increase calories, increase metabolism)

As you gain weight your body has a higher set point for the amount of calories you need. (obese people have higher insulin levels.) Eating less does not result in lasting weight loss because as you gain weight your set point for the amount of calories your body needs increases.
What is important is learning how to reduce your set point. (I did not get to this part yet on how to do this.)

Insulin causes Obesity.

"Obese patients tend to have a higher fasting insulin level, as well as an exaggerated insulin response to food."

The longer you are obese the more insulin resistant get are so you need to produce more insulin to make your body obtain energy at the same level (making you fatter).

"So we know that insulin causes insulin resistance. But insulin resistance also causes high insulin—a classic vicious or self-reinforcing, cycle. The higher the insulin levels, the greater the insulin resistance. The greater the resistance, the higher the levels. The cycle keeps going around and around, one element reinforcing the other, until insulin is driven up to extremes. The longer the cycle continues, the worse it becomes—that’s why obesity is so time dependent. People who are stuck in this vicious cycle for decades develop significant insulin resistance. That resistance leads to high insulin levels that are independent of that person’s diet. Even if you were to change your diet, the resistance would still keep your insulin levels high. If your insulin levels stay high, then your body set weight stays high. The thermostat is set high, and your weight will be drawn irresistibly upward. The fat get fatter. The longer you are obese, the harder it is to eradicate."

Low-fat diet does not work for long term. Lowering calories does not work for long term. low-carb diet does not work long term. Just because carbs raises insulin does not mean it makes people fat. ex: People in china eating a lot of rice(carbs) are not getting fat.

Eating small meals many times a day is NOT good for you. It keeps you in the insulin dominant state for longer. Which makes it easier for insulin resistance to develop. (Sleeping keeps you in the insulin deficient state.)

Breakfast is stupid. I KNEW IT GODDAMMIT! I'm never hungry at breakfast and this book says when you wake up your body already gives you energy without it. (For the most part. If you are hungry at this time the book says you should eat.)

"To put it simply, you cannot eat more to weigh less, even if the food you’re eating more of is as healthy as vegetables." (Replace eating unhealthy food with vegetables NOT ADD eating vegetables to lose weight.)

"Giving insulin for type 2 diabetes will worsen, not improve, the disease. But can lowering insulin levels cure type 2 diabetes? Absolutely. But the many misunderstandings about type 2 diabetes would require another book to clarify."
Yeah as I was reading this book I was like... wait then why is insulin given for type 2 shouldn't insulin only be given for type 1 diabetes. So insulin really is bad for type 2.

Highly refined carbohydrates causes obesity. (ex: sugar, flour)

"Calories do not drive weight gain, and thus reducing them will not lead to weight loss."

How to lose weight (reduce sugar, reduce snacking):
Reducing sugar and refined carbohydrates will reduce insulin. Reducing snacking frequency prevents persistent high insulin levels, a key component of insulin resistance. These strategies lower insulin levels—the crucial, central problem of obesity.

"Bags of jellybeans and other candies were proudly proclaiming themselves to be fat free. The fact that they were virtually 100 percent sugar didn’t seem to bother anybody. Sugar consumption rose steadily from 1977 to 2000, paralleled by the rising obesity rates."

"Sugar, more than any other refined carbohydrate, seems to be particularly fattening and leads to type 2 diabetes."

"FRUCTOSE: THE MOST DANGEROUS SUGAR" " high-fructose corn syrup"

"fructose produces only a mild rise in insulin levels compared to glucose, which led many people to regard fructose as a more benign form of sweetener. Fructose is also the main sugar in fruit, adding to its halo. An all-natural fruit sugar that doesn’t raise blood sugars? Sounded pretty healthy. A wolf in sheep’s clothing? You bet your life. The difference between glucose and fructose will very literally kill you."
(Natural fructose from fruit does not add that much to the diet like high fructose corn syrup so it's not that bad. It's the extremely high proportion of fructose the corn syrup is adding to the diet that is causing obesity.)

"Whereas almost every cell in the body can use glucose for energy, no cell has the ability to use fructose."

"The glucose group showed no change in insulin sensitivity. The fructose group, however, showed a 25 percent worsening of their insulin sensitivity—after just seven days!"

"The fructose, but not the glucose group, developed pre-diabetes by eight weeks. Insulin levels as well as measures of insulin resistance were significantly higher in the fructose group."

"Sucrose, a fifty-fifty mix of glucose and fructose, therefore plays a dual role in obesity. Glucose is a refined carbohydrate that directly stimulates insulin. Fructose overconsumption causes fatty liver, which directly produces insulin resistance."

"Sucrose stimulates insulin production both in the short term and in the long term. In this way, sucrose is twice as bad as glucose."

"Sugars are not simply empty calories or refined carbohydrates. They are far more dangerous than that, as they stimulate both insulin and insulin resistance. The extra fattening effect of sugar is due to the stimulation of insulin resistance from fructose, which festers for years or even decades before it becomes obvious." (Sucrose is also the really bad sugar.)

"Carbohydrates are not inherently fattening. Their toxicity lies in way they are processed."
"we now predominantly eat refined grains as our carbohydrate of choice." (refined carbohydrates are the bad ones)

"The key to understanding fiber’s effect is to realize that it is not as a nutrient, but as an anti-nutrient—where its benefit lies. Fiber has the ability to reduce absorption and digestion. Fiber subtracts rather than adds." (Fiber is the "antidote" to carbohydrates the "poison".)

"It is no coincidence that virtually all plant foods, in their natural, unrefined state, contain fiber. Mother Nature has pre-packaged the “antidote” with the “poison.”"
Profile Image for Crystal Starr Light.
1,350 reviews819 followers
October 4, 2018
Bullet Review:

Mixed bag. On one hand this is one of the only health books I've ever listened to that actually said "Different people gain weight for different reasons" and "All diets work in the beginning". Basic, but somehow still shocking.

On the other hand, this book is another one of those "Diets don't work, so do my diet". Um, really? Calories in =/= Calories out so let's just not eat for several days and we'll see the weight slide off. And this business of "religions fast, so we should to" (Why? Should we also condemn pork and divorce and tattoos and mixed fabrics because religions do that?) and "people have fasted for 382 days without serious effects" (people have died from this) HIGHLY suspect. It's so bizarre a book that says "all diets work" ends up saying "intermittent fasting is the only way" - something science isn't showing to be true.

On a different note: this book takes FOREVER to get to the author's preferred diet method, overusing to the point of abuse the phrase, "Insulin resistance causes obesity".

Not the worse diet/health book; I think that's what makes the flaws so frustrating.
Profile Image for Arezoo Gholizadeh.
Author 20 books81 followers
January 16, 2021
به نظرم همه باید این کتاب رو یه بار بخونن تا تمام تصوراتشون از مفاهیم چاقی، کالری، متابولیسم و تغذیه زیرورو بشه...البته کل این تحول بر اساس تحقیقات علمیه. اگه از دیدن و شنیدن مطالبی که پایه‌ی علمی ندارن خسته شدین و واقعا می‌خواین بدونین بدن و غذا چطور کار می‌کنن، این کتاب مال شماست. حدود بیست درصد از حجم کتاب فقط رفرنس علمیه و نویسنده اونقدر می‌گه که بالاخره جا بیفته :)) البته این رفرنس‌ها به موقع کاربردی می‌شه و در حد تئوری نمی‌مونه.
من اصلا نمی‌خوام درباره جزئیات داده‌های کتاب بگم چون نویسنده طوری به مسائل پرداخته که موقع خوندن کتاب بارها مثل خوندن یه رمان هیجان‌زده شدم، گاهی حتی می‌خواستم مثل جوئی کتاب رو توی فریزر بذارم. نگارش این کتاب هنرمندانه بود و سیر منطقی و درستی رو دنبال می‌کرد.

The bottom line: if you care about your health, read this!

بیست‌وهفتم دی‌ماه نودونه
Profile Image for Monica.
592 reviews621 followers
December 5, 2019
Hmm cut out sugar, cut out processed foods, cut out flour and routinely skip miss a meal on purpose a couple of times a week (fasting). Insulin and insulin resistance are the reasons that people have problems losing weight. Calorie counting doesn't work. Exercise is healthy and helpful in lots of ways that are important to our well being, but for actual weight loss (long term), not so much. Actually for the most part this book made sense on the surface. Time will tell if it's viable. May have a more in depth review later after applying some of Fung's concepts...

4ish Stars

Listened to the audio book. Brian Nishi was very engaging.
457 reviews12 followers
June 21, 2016
I had just finished watching Jason Fung's six part video series, The Etiology of Obesity on YouTube, and it crystallized a lot of what I've learned over the years regarding hormones and weight loss/gain, so I thought I'd pick up the book and see what else he had to say.

Well, honestly, most of the stuff he talks about in the book is in the videos (which I sort of figured), so you don't really need the book, though it's nice to have a more convenient reference than twitching through YouTube.

I used to get into arguments with a guy who'd smugly assert that calorie intake versus output is all you need to know for weight loss, which is sort of like saying all you need to understand a plane crash is that drag was greater than lift at some point. This is true, and also useless.

It's interesting to note that, every attempt to prove that "eat less/exercise more" would result in weight loss has failed, scientifically. Which factors into something I observed a while ago, which is that you can't exercise enough to make up for diet deficiencies. (Even Olympic swimmer Michael Phelps could count burning most of his legendary 12,000 calorie diet to heating his body—not exercise.) But we love this model because it allows us to think badly of others (and ourselves), not because it's accurate.

What this book does is address the hormonal causes of obesity: What causes hunger, why do people overeat, why does the body react to low calories by shutting down (rather than burning fat), and so on. And it's pretty easy to demonstrate the accuracy of what's being said (at least short term).

Fung points out, though, that every diet works short term. (Another observation I had made years ago, when literally anything I tried to lose weight worked.) Long term, though, they all fail.

Another big piece of the puzzle comes in the WHEN to eat. Despite being surrounded by food (or perhaps because) we are bizarrely anxious about our next meal. You'd be surprised how long you can go without food, and how good it can feel (quite apart from its other benefits). But this also makes sense: Feast and famine had to be a part of human evolution. We are not cows or other grazing animal.

I think Fung's on a little less solid ground scientifically regarding artificial sweeteners and certain other food additives. It's not a bad rule of thumb to avoid them, since some are demonstrably quite bad, but I'm not sure there isn't a baby/bathwater situation here.

Anyway, laboriously footnoted (about a third of the book is footnotes!), and very to the point, this is well worth a read for anyone interested in the subject of how bodies work.
Profile Image for Cindi Seal.
5 reviews2 followers
May 30, 2017
Dr. Fung does a great job convincing that insulin and insulin resistance cause weight gain (as opposed to the overly simplistic and flawed calorie deficit model); however I was disappointed when reaching the end of the book. I understand no one book or person will have the answer/cure for obesity, but reading the recommendations for fasting, only to find that weight loss differs from person to person using this method and that there are plateaus using fasting made me raise my eyebrow. If he is claiming that reducing insulin will lead to weight loss and that fasting reduces insulin and increases insulin sensitivity, then it should follow that reducing insulin through fasting should work more consistently and across the board; else explain WHY this is not the case. And if fasting has the same susceptibility to being thwarted by the body's tendency towards homeostasis, then how is it really any better than other methods which are also vulnerable to the same thing? Why not push anti-homeostasis methods in general (I.e. When weight loss stalls, change the routine, etc.)? Additionally, the book was lacking evidence of the long term efficacy of intermittent fasting. If you are touting a particular method for weight loss, apply the same scrutiny to that method that you applied to the others you destroyed earlier and show that it holds up (in particular, showing that it stands the test of time; long term -- > 5, 10 years -- weight loss and normal weight maintenance.) Lastly, I was a bit surprised that he did not address the elephant in the room: anorexia. I think it would benefit him to at least address this and caution against fasting for those who may be particularly susceptible to eating disorders (or at least be medically supervised, if so.) Beyond these criticisms, the book contains a lot of useful information, and I believe he makes a lot of successful arguments against past tropes of dietary advice for weight loss.
Profile Image for Ladan.
184 reviews344 followers
March 16, 2021

Fun, easy to read, and indeed science-based stuff on what to eat, when to eat to run a healthy life. If you care about your health, you really should read this.
Profile Image for Mehrnaz.
144 reviews93 followers
November 26, 2020
یه نفر نوشته :
Great book! Horrible title!

این کتاب فارق از اسمش، که از کد برای چاقی‌های خیلی شدید حرف میزنه، پر از اطلاعات مفید و معتبر در زمینه‌ی تغذیه است.
یه نفر دیگه هم نوشته بود که اگر قرار باشه یه کتاب برای افزایش معلومات تغذیه‌ای‌تون بخونید، اون همین کتابه. من با هر دوی این دو نفر خیلی موافقم. این کتاب واقعا اطلاعاتم رو در این زمینه درست کرد. اگر تصمیم دارین در این زمینه مطالعه کنید، این کتاب می‌تونه گزینه‌ی مناسبی باشه.

پ.ن. مچ خیلی از چرت و پرت گویی‌های اساتید اینستاگرام رو میشه با این کتاب گرفت(البته هدف گول نخوردنه)! یه نفر از روی تیتر کتاب که به عنوان مرجع براش آوردم، خواست بهم ثابت کنه که نتایج متناقضه و حرف خودش درسته! لینک مقاله‌ای که کتاب بهش ارجاع داده بود رو براش فرستادم، سکوت کرد. مقاله‌ی خفن و معتبری بود. این رو گفتم که اضافه کنم حرف‌های این کتاب پشتیبانه‌ی علمی خیلی معتبری دارند.
Profile Image for Odai Al-Saeed.
875 reviews2,412 followers
May 27, 2019
إن كتب التوعية الثقافية للعملية الغذائية ونمطها الغذائي عادة ما يتخللها حشو ومعلومات زائدة لا تعني شيئاً للقارئ
وفي كتاب " شيفرةالبدانة" هناك أمران مهمان أولها هو المعلومات المضافة التي سوف تعود بأثر إيجابي لمن ينشد تخفيف الوزن والثاني هو الحل كأسلوب حياة من خلال ارشادات معقولة ومبسطة سوف يحتوي عليها الفصل الأخير من الكتاب هذا بالإضافة إلى بعض المتعة النوعية التي تفرق عن كتب تتعاطى ضمن هذا النسق والسياق... كتاب جيد
Profile Image for Mustafa Nuwaidri.
378 reviews143 followers
November 10, 2019
كتاب في محاربة البدانة
يبدو تخصصيا قليلا، ومسهبا كثيرا بحيث تحتاج ان تقرأ صفحات كثيرة بلا طائل من اجل ان تستخلص نصيحة بسيطة سأقولها في السطور التالية

1- الحلويات والسكريات هي أسوء من الدهون
2- الرياضة تخفف الوزن ولكن ليست هي العامل الأهم
3- السبب الرئيس في زيادة الوزن هو افراز الانسولين
4- يفرز الانسولين مع كل مأكولات تدخل بطنك ، وتفرز بافراط مع السكريات او الكربوهيدرات المكررة
5- اي ان الخبز الابيض والارز الابيض والكعك والحلويات والسكر والاسكريم والعصير وغيرها امور سترفع الانسولين وستسبب السمنة
6- هناك امر آخر، يجب عليك ان تتناول 3 وجبات في اليوم لا اكثر، وان تصوم في غير هذه الوجبات عن الأكل، لا وجبات خفيفة لانها ستبقي الانسولين مرتفعا طوال الوقت، يجب ان تبقي مستوى الانسولين منخفضا في اغلب ساعات اليوم.
7- السعرات الحرارية مجرد خدعة ، تناول الكثير من الخضروات مهما زاد عدد سعراتها ولا تأكل السكاكر مهما قل عدد سعراتها
Profile Image for Zahra Naderi.
302 reviews55 followers
February 25, 2021
«یه کتاب عالی، با یه عنوان بد.»

زمانی که بعد از قرص خوردن و رژیم سختی که گرفتم، وزنم خیلی کم شد، یه نفر از آدمای دور و برم به‌م گفت «دنیا به آدمای چاق هم نیاز داره.» ولی این حرف مثل این می‌مونه که بگی «دنیا به بیماران مبتلا به سرطان هم نیاز داره.»
این حرف خیلی بی‌معنی‌ئه. چون اساسا ربطی به هم ندارند.

چاقی یه بیماری‌ئه. نه این که بخوام بگم «باعث» بیماری‌های دیگه می‌شه و به این دلیل بیماری‌ئه. نه، چاقی یه اختلال هورمونی‌ست که چون درجا ما رو نمی‌کشه، به چشم بیماری نمی‌بینیم‌ش.
و این «بیماری ندیدن»ش باعث می‌شه مسئله رو ربط بدیم به اراده‌ی شخص و اعتماد به نفس‌ش رو لگدمال کنیم. کاری که جامعه و متخصص‌های تغذیه انجام‌ش می‌دن.

این کتاب، دلیل اصلی چاقی رو توضیح می‌ده، از باورهای غلط مثل کم‌بخور و زیاد ورزش کن و افسانه‌ی کالری پرده برداری می‌کنه، ایرادات رژیم‌های مختلف رو می‌گه و در نهایت راه‌حل ارائه می‌ده. و تمام این صحبت‌ها علمی‌ست. و شاهکار کتاب اینه که اصلاً خسته‌کننده نیست.

× خوندن‌ش رو به همه توصیه می‌کنم.
×× این که چی «بخوریم» که لاغر بشیم هم فقط تو قصه‌هاست.
××× کانال یوتیوب دکتر فانگ هم خیلی کمک‌کننده‌ست.
Profile Image for Krista.
1,366 reviews542 followers
October 27, 2019
Once we understand that obesity is a hormonal imbalance, we can begin to treat it. If we believe that excess calories cause obesity, then the treatment is to reduce calories. But this method has been a complete failure. However, if too much insulin causes obesity, then it becomes clear we need to lower insulin levels.

My back story, which isn't necessary for this review: My sister-in-law heard that The Obesity Code by Dr. Jason Fung (a Toronto nephrologist who treats the end stages of livers damaged by “diabesity”) has a radical new theory of what makes and keeps us overweight; so I bought and read the book in an evening. I can report that Fung's conclusions make sense (they certainly explain my own experience), and with humour and easy-to-understand analogies, his book is a very readable scientific history of how the medical and dietary establishments have failed in their recent approach to fighting obesity (it's no coincidence that obesity rates rose dramatically at the same time both were pushing low fat/high carb diets). But as readable as I did find Fung's history of scientific research into obesity, I don't know if this is what everyone is looking for in a book like this: my sister-in-law, who is not a reader, would do well to take it as given that Fung has properly read and interpreted the studies and skip right to the last two chapters on what to eat and when to eat. His basic conclusion: Excess calories don't make us gain weight, excess insulin does. Excess insulin is produced when we consume too much added sugar, too many overprocessed carbohydrates, or eat too often during the day so that our insulin levels never have a chance to go down. Persistent excess insulin leads to insulin resistance, which forces us to eat more and spike our insulin higher, leading to even more weight gain. This eventually sets our body weights higher – so that if we consume fewer calories, our bodies will compensate by burning fewer calories – leading to weight loss plateaus that can only be overcome by changing up our dietary plans every few months or intermittent fasting. Everything Fung writes makes total sense; so many ideas made me think, “But I knew that already, didn't I?” That's the long and longer of it and I'll just add a few more ideas that were particularly interesting to me (also not necessary to read as part of this review):

Hormones are central to understanding obesity. Everything about human metabolism, including the body set weight, is hormonally regulated. A critical physiological variable such as body fatness is not left up to the vagaries of daily caloric intake and exercise. Instead, hormones precisely and tightly regulate body fat. We don't consciously control our body weight any more than we control our heart rates, our basal metabolic rates, our body temperatures or our breathing. These are all automatically regulated, and so is our weight. Hormones tell us when we are hungry (ghrelin). Hormones tell us we are full (peptide YY, cholecystokinin). Hormones increase energy expenditure (adrenalin). Hormones shut down energy expenditure (thyroid hormone). Obesity is a hormonal dysregulation of fat accumulation. Calories are nothing more than a proximate cause of obesity.

I appreciated how often Dr. Fung reiterated that “Move more, eat less” simply doesn't work – even if this maxim has made it very easy for doctors and laypeople to fat shame those who are persistently overweight (that plus-sized person is both gluttonous and slothful; two of the Deadly Sins; obviously no self-control), that's not how weight gain works. We do have control over what and when we eat – which does cause weight gain – but with the medical establishment and government food guides both giving us bad advice for the past fifty years (carbohydrates should not make up the base of the food pyramid; there is zero evidence that fat accumulates in the arteries to cause heart disease; breakfast is not the most important meal of the day and can be safely skipped in order to prolong insulin depletion), so many people are in the same boat as I am: simply no clue how to eat. Fung's prescription:

Reduce your consumption of added sugars. Reduce your consumption of refined grains. Moderate your protein intake. Increase your consumption of natural fats. Increase your consumption of fiber and vinegar.

In addition, Fung recommends only three meals per day (it is also no coincidence that obesity started to rise in conjunction with the idea that we need snacks in between meals; humans are not grazing animals) and to stretch the fasting period between our last meal of the day and our first for as long as possible. And when weight loss plateaus, it's time to fast: Fung adds an appendix to this book which shows how to achieve a twenty-four or thirty-six hour fasting schedule, and with plenty of fluids (including broth at midday), he assures the readers that they won't be uncomfortable after the initial jolt; and besides, intentional fasting has always been a part of traditional human society:

This is the ancient secret. This is the cycle of life. Fasting follows feasting. Feasting follows fasting. Diets must be intermittent, not steady. Food is a celebration of life. Every single culture in the world celebrates with large feasts. That’s normal, and it’s good. However, religion has always reminded us that we must balance our feasting with periods of fasting – “atonement,” “repentance” or “cleansing.” These ideas are ancient and time-tested. Should you eat lots of food on your birthday? Absolutely. Should you eat lots of food at a wedding? Absolutely. These are times to celebrate and indulge. But there is also a time to fast. We cannot change this cycle of life. We cannot feast all the time. We cannot fast all the time. It won’t work. It doesn’t work.

Overall, I trust that Fung is onto something with his insulin-resistance theories; obviously, what I've been told about appropriate nutritional choices my entire life isn't the whole picture. I'm not, however, 100% convinced that his approach in this book – while admittedly of adequate interest to me personally – will be engaging for every reader: you need to get through many pages of “The government pushed cheap, processed carbs as the bulk of the recommended diet for decades because they also subsidized farmers who grew wheat and corn, leading us to overpaying taxes to both produce our own poisons and medically treat their effects after the case” and “The medical establishment continues to push 'Move more, eat less' as the key to weight loss because, even though it doesn't work, it puts the onus on the patient to manage their own care”: a little too much smacks of conspiracy theory, which I've seen far too much of in books on nutrition. However: I have learned over the last year that eliminating processed foods and refined carbs makes food that tastes good and makes me feel good. The piece I was missing, I guess, was the intermittent fasting – and I'll have to really consider if that will make sense for me.
Profile Image for John.
481 reviews13 followers
March 12, 2016
I have struggled for most my adult life to keep my weight at a healthy level. Usually this means going on a major diet for several months every few years. I'm doing that now, and have lost more than 25 pounds. It feels good. But over the past eight weeks or so, even though I've kept to my diet, the weight has stopped coming off. Very discouraging.
So Jason Fung's book explains this phenomenon--and much else. He explains how a focus on calories misses the important role that insulin plays in weight regulation, and explains at length the issues surrounding processed food--especially when it comes to both insulin and insulin-resistance.
This isn't really a diet book. No recipes. But he does lay out some common sense suggestions for breaking through the plateau barrier. Lots of interesting science along the way. Jason Fung is a doctor who specializes in Diabetes. I recommend this book!
Profile Image for Rebecca Jo.
467 reviews56 followers
August 9, 2018
I've got so many emotions on this book.
It started off full of detailed information - & read easy enough for someone to understand that isn't a doctor or a dietitian. Some facts that were eye opening & it did a really good job of explaining how insulin & cortisol are the big contributors to the yo-yo of weight gain. I even at one point was like, This needs to be a documentary.
It left me sort of feeling defeated reading how badly diets dont work & how its like a loosing fight trying to eat healthy, or watch the carbs, or proteins, & repeating over & over how exercise doesnt work or change anything.
The detail & information was so in depth - & at times, repetitive, which I thought was trying to emphasis the point - so I was so excited to get to the end of the book. The HOW to apply all of this information.
Except at the end, I felt totally let down. Like that Sesame Street Book where "There's a Monster at the end of this book" - only to see its just a let down.
Literally, his answer is to eat a balanced, clean diet. After he pretty much downed it the whole book... & then the BIG SECRET of it all? Fasting.
& I get that it may be something to look into, but we just read over 300 pages about diet & nutrition & how bodies work with insulin & we get one little appendix that says to fast for a few days a week. No big detail or research, except a lot of "people have been doing it for years - even Jesus & Buddha" sort of thinking. & the thing that got me with that, he even says that it will come to a time where you will plateau. Isn't that what he just dogged out other methods of loosing weight for doing?
I'm just frustrated. I felt like it was a total let down at the end.
& I will say, I am intrigued to look more into intermittent fasting - though he's suggesting going like 36 hours (or longer if you can) just to see how it makes me feel & if there are any changes in my body because of it.
All of this to say, Mr. Fung pointed out so many times in the book how diets in our country were like a good business scam. How America promotes eating 6 times a day, eat breakfast, eat more protein, eat cleaner, eat more superfoods.... why? "Because no body makes any money when you eat less".... but in the end, I feel like this book has a bit of a scam on it as well - just telling you NOT to eat at all for hours on end - even after a chunk of the book is drilled in our head "Eat Less DOES NOT WORK! FACT! ACCEPT IT" That's a direct quote....
A lot of contradiction.
Profile Image for Saja Salih سجى صالح.
59 reviews57 followers
July 1, 2021
رغم طول الكتاب نسبيًا(304 صفحة) إلا أنه ممتع و مفيد جدًا و مليء بالأفكار الغير مطروقة عن الحمية الغذائية و انواعها و خرافة السعرات و غيرها..

أستمتعت بقرأته عكس ما توقعت😅، و انصح بقرأته لكل مهتم بالتغذية و الصحة بشكل عام.

ps. ازلت نجمة واحدة لانه كان وجود بعض المقاطع برأيي لا حاجة له و كانت لجعل الكتاب اطول فقط.
Profile Image for Moonkiszt.
2,041 reviews212 followers
May 10, 2019
So. The secret, the ancient wisdom lost in the ages is fasting. Dr. Fung's point is that we are focusing on the wrong things - that insulin causes obesity, and we need to work on getting our insulin balances balanced and the way that is done is through periods of low insulin (fasting) and higher insulin (feeding) - of course he refers those who have known issues to check out plans with their docs. Other tips are avoid sugar, fake sugar and cola; sauces of all types; avoid highly processed anything - protein bars, cereals, powdered shakes, anything that makes your drinks or food tastier. Stick with veggies, fruit, grains, high fibered anything. Oh, and apple cider vinegar - coupla tablespoons a day.

It's a great book, with a different way of thinking. But like all books about religion or politics, ideas about how to manage the ins and outs of our orifices is just as controversial with plans that range a full 360. . . .

I'm gonna try it. I may or may not report back.
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