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April 30 - May 1, 2024
A recent study showed that only 12 percent of Americans are metabolically healthy, which means that only 12 percent of Americans have a perfectly functioning body—including healthy glucose levels. Odds are that you, and nine out of the ten people closest to you, are on a glucose roller coaster without knowing it.
Here are some questions to ask yourself to find out if your glucose levels are dysregulated. Have you been told by a doctor that you need to lose weight? Are you trying to lose weight but finding it difficult? Is your waist size (or pant size) above 40 inches if you are a man or above 35 inches if you are a woman? (Waist size is better for predicting underlying disease than BMI is.) Do you have extreme hunger pangs during the day? Do you feel agitated or angry when you are hungry, aka hangry? Do you need to eat every few hours? Do you feel shaky, lightheaded, or dizzy if meals are delayed? Do
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But what the ADA describes as “normal” may not actually be optimal. Early studies showed that the thriving range for fasting glucose may be between 72 and 85 mg/dL. That’s because there is more likelihood of developing health problems from 85 mg/dL and up.
The ADA states that our glucose levels shouldn’t increase above 140 mg/dL after eating. But again, that’s “normal,” not optimal. Studies in nondiabetics give more precise information: we should strive to avoid increasing our glucose levels by more than 30 mg/dL after eating. So in this book I will define a glucose spike as an increase in glucose in our body of more than 30 mg/dL after eating.
A glucose spike from a sweet food (cupcake) is worse for our health than a glucose spike from a starchy food (rice). The reason has nothing to do with the glucose measured, though; it has to do with a molecule that’s not visible. A sweet food contains table sugar, or sucrose—that compound made up of glucose and fructose. A starchy food doesn’t. Whenever we see a glucose spike from a sweet food, there is a corresponding fructose spike that unfortunately we can’t see.
Until they do, remember that if the food you ate was sweet and it created a glucose spike, it also created an invisible fructose spike, and that’s what makes a sweet spike more harmful than a starchy spike.
Oxidative stress is a driver of heart disease, type 2 diabetes, cognitive decline, and general aging. And fructose increases oxidative stress even more than glucose alone. That’s one of the reasons that sweet foods (which contain fructose) are worse than starchy foods (which don’t). Too much fat can also increase oxidative stress.
Fructose molecules glycate things 10 times as fast as glucose, generating that much more damage. Again, this is another reason why spikes from sugary foods such as cookies (which contain fructose) make us age faster than do spikes from starchy foods such as pasta (which doesn’t).
Glucose levels and glycation are so connected that a very common test to measure the level of glucose in our body actually measures glycation. The hemoglobin A1c (HbA1c) test (well known among diabetics) measures how many red blood cell proteins have been glycated by glucose over the past two to three months. The higher your HbA1c level, the more often the Maillard reaction is happening inside your body, the more glucose is circulating, and the faster you are aging.
Once insulin has stored all the glucose it can in our liver and muscles, any glucose beyond that is turned into fat and stored in our fat reserves. And that’s one of the ways we put on weight. And then some. Because it’s not just glucose that our body has to deal with, it must also dispose of fructose. And unfortunately, fructose cannot be turned into glycogen and stored in the liver and the muscles. The only thing that fructose can be stored as is fat.
Ironically, processed foods that are “fat free” often contain a lot of sucrose, so the fructose in it is turned into fat after we digest it.
Are you hungry all the time? You are not alone. First, many of us feel hungry again shortly after we eat—and here again, it has to do with glucose. If you compare two meals that contain the same number of calories, the one that leads to a smaller glucose spike will keep you feeling full for longer.
What the researchers discovered was fascinating. When the subjects’ glucose levels were stable, they didn’t rate many of the foods highly. However, when their glucose levels were decreasing, two things happened. First, the craving center of their brain lit up when pictures of high-calorie foods were shown. Second, the participants rated those foods much higher on the “I want to eat it” scale than when their glucose levels were stable.
A common symptom of dysregulated glucose is waking up suddenly in the middle of the night with a pounding heart. Often, it’s the result of a glucose crash in the middle of the night.
It’s a young field of study, but data proves that women with insulin resistance are twice as likely to have regular migraine headaches than women who don’t. When sufferers’ insulin levels are lowered, things seem to get better: when treated with a medication that reduced the amount of insulin in the body, over half of a group of 32 people experienced a significant reduction in migraine frequency.
In a study in males aged 15 to 25, the diet that resulted in the flattest glucose curves led to a significant reduction in acne compared to a diet that caused glucose spikes. (Interestingly, they saw improvements even without reducing other foods known to contribute to acne, such as dairy products.)
When we talk about heart disease, cholesterol is often the main topic of conversation. But that conversation is shifting; we’ve discovered that it isn’t just a matter of “too much cholesterol.” In fact, half the people who have a heart attack have normal levels of cholesterol. We now know that it’s a specific type of cholesterol (LDL pattern B) as well as inflammation that drive heart disease. Scientists have found out why this is the case. And it’s linked to glucose, fructose, and insulin.
The lining of our blood vessels is made of cells. Heart disease starts when plaque accumulates underneath that lining. These cells are particularly vulnerable to mitochondrial stress—and glucose and fructose spikes lead to oxidative stress. As a result, these cells suffer and lose their smooth shape. The lining of the vessels becomes bumpy, and fat particles get stuck more easily along the uneven surface.
When our levels of insulin are too high, our liver starts producing LDL pattern B. This is a small, dense kind of cholesterol that creeps along the edges of the vessels, where it’s likely to get caught. (LDL pattern A is large, buoyant, and harmless—we get it from eating dietary fat.)
Finally, if and when that cholesterol is oxidized—which happens the more glucose, fructose, and insulin are present—it lodges under the lining of our blood vessels and sticks there. Plaque builds up and ob...
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To add to the problem, statins lower LDL pattern A, but they don’t lower the problematic pattern B. This is why statins don’t decrease the risk of a first heart attack.
Doctors can better measure heart disease risk by looking at what’s called the triglycerides-to-HDL ratio (which tells us about the presence of the small, dense LDL pattern B), and C-reactive protein (which tells us about inflammation levels). Triglycerides become LDL pattern B in our bodies. So by measuring triglycerides, we can gauge the amount of the problematic LDL pattern B in our system. If you divide the level of triglycerides (in mg/dL) by HDL level (in mg/dL), you’ll get a ratio that is surprisingly accurate in predicting LDL size. If the result is smaller than 2, that’s ideal. If the
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Two meals consisting of the same foods (and therefore the same nutrients and the same calories) can have vastly different impacts on our body depending on how their components are eaten. I was taken aback when I read the scientific papers that proved this, notably a seminal one out of Cornell University in 2015: if you eat the items of a meal containing starch, fiber, sugar, protein, and fat in a specific order, you reduce your overall glucose spike by 73 percent, as well as your insulin spike by 48 percent. This is true for anyone, with or without diabetes. What is the right order? It’s fiber
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Fiber has three superpowers: First, it reduces the action of alpha-amylase, the enzyme that breaks starch down into glucose molecules. Second, it slows down gastric emptying: when fiber is present, food trickles from sink to pipe more slowly. Finally, it creates a viscous mesh in the small intestine; this mesh makes it harder for glucose to make it through to the bloodstream. Through these mechanisms, fiber slows down the breakdown and absorption of any glucose that lands in the sink after it; the result is that fiber flattens our glucose curves.
Foods containing fat also slow down gastric emptying, so eating them before rather than after carbs also helps flatten our glucose curves. The takeaway? Eating carbs after everything else is the best move.
Next time you sit down for a meal, eat the veggies and proteins first and the carbs last. Note how you feel after eating compared to how you usually feel after a meal.
There’s a scientific explanation for this improvement in her hunger: the Cornell research team showed that if we eat our food in the wrong order (starches and sugars first), ghrelin, our hunger hormone, returns to premeal levels after just two hours. If we eat our food in the right order (starches and sugars last), ghrelin stays suppressed for much longer. (They didn’t measure past three hours, but looking at the trends, I think it fair to say that it stays down for five to six hours.)
I categorize fruits in the “sugars” category, because although they contain fiber, they are made up mostly of glucose, fructose, and sucrose—aka sugars. Therefore they should be eaten last.
Based on the science, I love any meal that starts with a salad. Unfortunately, many dining experiences don’t set us up for success: restaurants serve bread while you’re waiting for food.
For instance, in a 2015 study, scientists in New Zealand fed participants two types of bread: regular bread and enriched bread with 10 grams of fiber per serving. They found that the additional fiber reduced the glucose spike of the bread by over 35 percent.
Talking about bread, here’s what you’re looking for if you want to enjoy some while flattening your curves: skip the loaves that claim to contain “whole grain,” which often don’t have much more fiber than their traditional “white” counterparts. Buy bread that is dark and dense, made from rye with a sourdough starter. It’s traditionally German and usually called seed bread or pumpernickel. Those contain the most fiber.
Think of your favorite veggie or salad. Prepare it with care, and eat it before every lunch and dinner for a week. Notice your cravings and whether they change.
When you are out at a restaurant and aren’t ordering starters, the main course side salad with olive oil and vinegar is your best ally. Order it, then eat it first. The fiber and fat will make any further starch arrival much smoother for your body.
So he devised a trick: before going out for dinner, at home, he made himself a big plate of grilled broccoli and ate it with salt and hot sauce. With broccoli in his belly, he was ready for his meal out. When he got to a restaurant, he wasn’t starving, so he could easily forgo the bread on the table. And anyway, the effect of whatever starch and sugar he now ate would be curbed by the broccoli. That meant less of a glucose spike and less insulin release, along with less inflammation, less damage to his cells, and less inching toward type 2 diabetes.
This study involved obese teenagers. They were asked to replace the calories in their diet that came from fructose with calories from glucose (they replaced fructose-containing foods such as doughnuts with foods containing glucose but no fructose such as bagels). The number of calories they consumed was kept constant. What happened? Their health improved: their blood pressure improved, and their triglycerides-to-HDL ratio (a key marker of heart disease, as we learned in part 2) improved. They started reversing the progression of their fatty liver and their type 2 diabetes. And this profound
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In fact, recent science shows that people who focus on flattening their glucose curves can eat more calories and lose more fat more easily than people who eat fewer calories but do not flatten their glucose curves.
What is true, however, is that if we are going to eat some sugar, a whole piece of fruit is the best vehicle for it. First, in a whole piece of fruit, sugar is found in small quantities. And you’d be hard pressed to eat three apples or three bananas in one sitting—which is how much can be found in a smoothie. Even if you did eat three apples or three bananas, you would take some time to eat them, much longer than it would take you to drink them in a smoothie. So the glucose and fructose would be digested much more slowly. Eating takes longer than drinking. Second, in a whole piece of fruit,
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An ideal breakfast for steady glucose levels contains a good amount of protein, fiber, fat, and optional starch and fruit (ideally, eaten last). If you’re buying breakfast at a coffee shop, get an avocado toast, an egg muffin, or a ham and cheese sandwich, not a chocolate croissant or toast spread with jam.
If you love oats (which are starch), eat them alongside nut butter, protein powder, yogurt, seeds, and berries. Avoid adding brown sugar, maple syrup, honey, tropical fruits, or dried fruit. You can try a chia pudding instead: chia seeds soaked overnight in unsweetened coconut milk with a spoonful of coconut butter.
Some cereals are better for your glucose levels than others. Look for those that brag about their high fiber content and low sugar content. (In the Cheat Sheets included at the end of this book, I’ll explain how to decipher nutrition labels on packaging to pick the best possible cereal.) Then eat it with 5% Greek yogurt instead of milk, which adds fat to the mix. Top with nuts, hemp seeds, and/or chia seeds to add protein to the mix. If you need to sweeten it, do so with berries—not sugar.
If you like to have a sweetened coffee drink, try mixing the coffee with full-fat milk or cream (fat is not to be feared) and sprinkling cocoa powder on top instead. Nondairy almond or other nut milks work, too,
Dried fruit, such as dates, have highly concentrated amounts of sugar, and they create big, unhealthy glucose spikes. Choose whole fruits over dried fruit.
For instance, agave syrup is often recommended to diabetics and women diagnosed with gestational diabetes because it has a “lower glycemic index” than table sugar. This is true—it does spike our glucose levels less. But the reason for this is that it contains more fructose and less glucose than regular table sugar. (Agave is about 80 percent fructose, compared to table sugar, which is 50 percent fructose.) And although this means the glucose spike it causes is smaller, the fructose spike is bigger. Now, get this: recall from part 1 that fructose is worse for us than glucose—it overwhelms our
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Other ingenious additions to either oatmeal or yogurt include cinnamon, cacao powder, cacao nibs, shredded unsweetened coconut, or unsweetened nut butter (I know it sounds strange, but nut butter tastes sweet and makes for a dessert-worthy combo).
The best sweeteners that have no side effects on glucose and insulin levels are: Allulose Monk fruit Stevia (look for pure stevia extract because some other forms of it are mixed with glucose-spiking fillers) Erythritol
There are some artificial sweeteners I’d recommend you avoid, because they are known to increase insulin and/or glucose levels, especially when combined with foods, or cause other health issues. They are: Aspartame Maltitol (turns to glucose when digested) Sucralose Xylitol Acesulfame-K
The best thing to do, in my opinion, is to use sweeteners to wean ourselves off the need to sweeten everything. Because sweetness is addictive.
We tend to spend about 20 hours of a 24-hour day in the postprandial state, because we have on average three meals and two snacks a day. This used to be different: up through the 1980s, people didn’t snack as often between meals, so they spent only 8 to 12 hours in the postprandial state. Snacking is a 1990s invention,
To increase your own metabolic flexibility, eat larger, more filling meals so you don’t need to snack every hour or two. That goes against a popular belief that eating “six small meals a day” is better than two or three big ones, but research bears it out. Scientists in the Czech Republic, in 2014, tested this in people with type 2 diabetes. They decided on a daily calorie quota and got one group of participants to consume their calories in two large meals and the other group to consume them in six small meals. The two-meal group not only lost more weight (8 pounds versus 5 pounds in three
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Same pineapple, different spike. If it’s eaten as a dessert after a meal containing fat, fiber, and protein, pineapple will create a smaller spike. We do see a small reactive hypoglycemia, but this is less of an issue than the big spike when pineapple is eaten as a snack. Bigger spike, more symptoms.
