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The Obesity Code: Unlocking the Secrets of Weight Loss

4.39  ·  Rating details ·  27,806 ratings  ·  3,111 reviews
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 prope
Kindle Edition, 330 pages
Published March 3rd 2016 by Greystone Books
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Danny McCaffrey Eat more fat? I think that's what Fung or Taubes would say.

Because "emotional eating" only came about as an explanation after the failure of Calories …more
Eat more fat? I think that's what Fung or Taubes would say.

Because "emotional eating" only came about as an explanation after the failure of Calories In/Out and the increasing obesity epidemic. Rather than take a critical look at CiCo the moral and behavorial explanations were invented such as emotional eating and the obese are lazy. Neither of which I believe anymore.

It's addiction. And all the ups and downs that come with the drug addiction of sugar. You eat sugar, it feels good. Then you crash. Feel hungry and blue. And eat more. That's the cycle of "emotional eating", but sugar is the problem (and lack of adequate essential fats). Not the emotions.

Fat turns off the switch that craves sugar. Is satisfying. And regulates hormones including those involving mood. Cut out sugar and eat more fat. (less)
Ashleigh I think alot of this has to do with insulin resistance. People who have higher insulin levels tend to have more central adiposity; they are the apple …moreI think alot of this has to do with insulin resistance. People who have higher insulin levels tend to have more central adiposity; they are the apple shaped people. The omentum, which is a collection of fat and blood vessels under the abdominal muscles that is also hormonally active, is part of that weight gain. By cutting carbs and intermittantly fasting, we can decrease this area. There are still problem areas, and some of this probably has to do with genetic predispositions to gain weight in certain areas, estrogen effect, and other issues. So losing the weight in one's thighs can be difficult, even after one's weight is in a normal range for BMI.(less)
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Chris Bartos
Oct 12, 2016 rated it it was amazing
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 pla
Otis Chandler
Feb 20, 2019 rated it it was amazing
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 (
Dec 26, 2016 rated it it was amazing  ·  review of another edition
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 or ...more
Theresa Alan
May 01, 2019 rated it really liked it  ·  review of another edition
“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,
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.
Aug 14, 2017 rated it it was ok  ·  review of another edition
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
Stephanie *Eff your feelings*
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
Cindy Rollins
Aug 06, 2017 rated it really liked it  ·  review of another edition
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 abou ...more
Angela Boord
Feb 03, 2017 rated it really liked it  ·  review of another edition
Shelves: diet-and-health
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. F ...more
Heather K (dentist in my spare time)

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
Phil Sykora
Jun 20, 2020 rated it did not like it  ·  review of another edition
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 b
Canadian Reader
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 ...more
Jan 10, 2018 rated it it was amazing  ·  review of another edition
Shelves: 4-star-5-star, 5-star
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.)
Crystal Starr Light
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"
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
May 26, 2016 rated it it was amazing  ·  review of another edition
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
Cindi Seal
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 c ...more
Mar 16, 2021 rated it really liked it  ·  review of another edition

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.
Krishna Chaitanya
I listened to the audiobook, the narrative is excellent, it has comical tone which helped in learning science facts easily.
Oct 27, 2019 rated it really liked it  ·  review of another edition
Shelves: 2019, can-con, nonfiction
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: (view spoiler)
Mar 12, 2016 rated it it was amazing  ·  review of another edition
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 weigh
Nikhil P. Freeman
Worked for me. Lost 18 pounds of fat in thirty days with a low-carb, high fat, moderate protein diet in conjunction with intermittent fasting.
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 anythi ...more
Lisa Kay
Aug 02, 2019 rated it it was amazing  ·  review of another edition
Please, please, please--if you are trying to decide if you should read this book or if this Way of Living is for you--and you see some reviewers’ post that this is basically a calorie reduction diet, ignore them! This doctor explains why calorie restriction does NOT work, and can actually be detrimental to your resting metabolic rate.

If a review you’ve read doesn’t discuss INSULIN and its affect on your body, then the reviewer obviously has NOT gotten the MAIN POINT of this book.

The cure isn’t
Rebecca Jo
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
Jun 13, 2018 rated it it was amazing  ·  review of another edition
Shelves: ebook-owned, audio
Probably the book I would now recommend as the place to start if you're interested in eliminating sugar & processed foods from your diet and making it stick... I think you really do need to understand the WHY of sugar elimination, not just the what, or else it doesn't last. He does a very nice job of breaking down why the calories in/calories out model doesn't sufficiently explain the underlying causes of obesity. I also appreciate that he sticks to human studies for his arguments ...more
Aneliya Petrunova
May 13, 2016 rated it really liked it  ·  review of another edition
(Прочетете по-долу на български)
Jason Fung's book "The Obesity Code" is a valuable addition to the library of anyone who is interested in healthy eating, obesity and weight loss. The author is a doctor (nephrologist) who has dedicated himself to fighting obesity and diabetes. He bases his book exclusively on studies done on humans (since humans are not rats and results from rat studies are not directly applicable to humans).

Dr. Fung presents his theory of the causes of obesity, blaming it first
Laura (Kyahgirl)
4/5; 4 stars; A-

This book was written by a Canadian doctor, a nephrologist in fact, who came to the topic by the way of treating patients for issues related to diabetes. I would highly recommend it for a couple of reasons. First, it gives a really good explanation of the all the hormones that impact blood sugar, hunger, saiety, metabolism, etc. And second it discusses aspects of nutrition that have been used to mislead consumers. Basically, food is big business, and those of us raised in the las
Feb 11, 2017 rated it it was amazing  ·  review of another edition
I'm not trying to lose weight, but this book is probably the best weight loss/diet book I've ever read. It's totally science and experiment based and doesn't mess around with your expectations--basically, it's really difficult to change your body's set point weight. The book explains how insulin is the main culprit and how to tackle that. Eye opening ...more
Sep 05, 2021 rated it it was amazing  ·  review of another edition
Very interesting with a lot of great information.
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114 likes · 38 comments
“But diet and exercise are not fifty-fifty partners like macaroni and cheese. Diet is Batman and exercise is Robin. Diet does 95 per cent of the work and deserves all the attention; so, logically, it would be sensible to focus on diet. Exercise is still healthy and important—just not equally important. It has many benefits, but weight loss is not among them. Exercise is like brushing your teeth. It is good for you and should be done every day. Just don’t expect to lose weight.” 20 likes
“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.” 12 likes
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