It is a pervasive myth in the low-carb and Paleo worlds, two worlds that are way too intertwined unfortunately, that when you eat lots of carbohydrates, insulin “spikes,” and, after many years of repeated insulin spiking, this leads to insulin resistance, worn out pancreatic beta cells, or both.
Search high and low, near and far, up and down, and over and out… But you’re unlikely to find much of anything that is very convincing that suggests that any part of this story is true. If you do manage to find a little fragment of something somewhere, it is usually not relevant to real life, and real life has an avalanche of contradictions against any theories one could build up to validate this myth somehow.
To begin with, as we touched upon in the chapter on Glycogen, those who are insulin sensitive typically have a good “spike” in insulin when they eat food. This allows glucose to quickly be packed away into muscle cells for later use and both the blood glucose levels and the insulin levels to return to baseline (and in a really insulin sensitive person like myself, blood glucose levels hardly ever rise – even after a big meal with hundreds of grams of carbohydrates).
This appears to be the healthy response to eating. Insulin resistant people have a totally different response, producing hardly any “spike” in insulin at all, followed by insulin levels gradually travelling up and then kind of lingering up high for a while before coming back down again. These peculiarities already gray the definitive lines that most people sketch up in their minds after reading through the popular paleo diet review materials.
More important are the obvious examples. Take a look globally. Are there correlations between the consumption of a diet heavily weighted towards carbohydrates and insulin resistance? Well, there is a relationship. It’s one called an “inverse correlation.” That’s one a them correlations that are like, reverse. In other words, the higher the diet is in carbohydrates by percentage of calories, the lower the likelihood for insulin resistance and things that often result from insulin resistance (such as obesity, early puberty, nearsightedness, type 2 diabetes, PCOS, and many others).
Although you shouldn’t need much more than a trip to Africa or Asia to really convince you that carbohydrates, the staples of a few billion people living in those areas, are inherently fattening compared to say, the diet of the Pima Indians (one of the highest fat diets in the world). I have found some of the research coming out of Africa to be particularly interesting. This includes the pioneering work of people like T.L. “Peter” Cleave, Hugh Trowell, and Denis Burkitt.
And I hate to bring this up, as there are a lot of other factors involved in this (protein restriction allows one to eat far more calories without weight gain), and these guys are completely bananas, but the fruit-based, low-fat raw vegans can certainly put away incredible amounts of carbohydrates and still have body fat levels of a concentration camp victim (as they love to point out to the Paleo crowd). Last week I watched one video of a kid who lost 140 pounds eating 750 grams of sugar per day, for example. But it’s not just them. Almost anyone can eat a fruit-based diet and lose tremendous amounts of body fat – even if calorie intake is very high. I had one guy lose over 50 pounds eating as much fruit as he could before noon every day last year – a guy that is extremely insulin resistant in fact.
Speaking of insulin resistance and carbohydrates, why is it that every book about reversing type 2 Diabetes is about increasing carbohydrate intake and eating tons of unrefined carbohydrates? I’m talking about the likes of John McDougall, Neal Barnard, Joel Fuhrman, Julian Whitaker, and Doug Graham here.
Now let’s not get too carried away. I could easily write a book bashing the myopic views of those that think plant-based vegetarian diets are fabulous when it comes not only to health, but even the control and/or reversal of type 2 diabetes. Only someone who can have a normal insulin and glucose response to a few slices of really good New York pizza and a big ass Sprite can consider themselves “cured” of the condition of diabetes. And carbohydrate restriction as well as fat restriction both cause the glucose and insulin response to pizza to get WORSE. I have devised strategies that actually improve the glucose and insulin response to common triggers of hyperglycemia, and that have no rebound effect.
Once again, what helps in the short-term usually hurts in the long-term, because short-term changes triggered by nutrition are often the mirror opposite of the long-term consequences. Just like with cutting calories to lose weight. Yeah, it makes you lose weight and all of your blood lipids and glucose levels and insulin levels and sensitivity and ALL of that improves. But it ignores the fact that decreasing caloric intake decreases metabolism and increases appetite and stress hormone production – leading to a huge rebound effect and a long-term worsening in all categories. The same could be said for all of these shitty diets that remove entire food groups. Keep your carbs or fats low enough for long enough, and eating even small amounts of the stuff you’ve been restricting will cause your blood sugar and insulin to go into the stratosphere (at least until you’ve eaten WITHOUT such restrictions for an extended period of time).
My best assessment of the physiology going on with insulin resistance and elevated insulin levels, although I have no plans of going into this in excruciating detail, is completely different than the carbs raise glucose raises insulin fairy tale circulating in the Paleo world. For starters, as we will get into in the next chapter, carbohydrates do not raise glucose or insulin levels. I encourage people to add carbohydrates to their diets to lower glucose and insulin levels, and they typically have fantastic results with it.
This is probably due to the fact that carbohydrates, particularly high-glycemic starches like grains and potatoes, decrease glucocorticoids – like cortisol. The lower the cortisol level, the greater the insulin sensitivity – barring adrenal failure/fatigue. Thus, glucose gets cleared easily from the bloodstream into the cells for storage and immediate use – like it does in a healthy person. When insulin resistance decreases, basal insulin levels naturally fall. When glucocorticoid secretion is reduced, you also see less overall activity in the adrenal glands. The adrenal hormones RAISE blood sugar, whereas insulin lowers blood sugar. Turn down glucocorticoid secretion – and carbohydrates play a vital role in achieving that, and both glucose and insulin levels fall. Neato.
Excesses of cortisol are known to cause not only impairment to glucose metabolism and fullblown type 2 diabetes, but basically every complication that comes with it – including belly fat, moon face (sometimes called “carbo face” by some of the weaker-minded people in the Paleo community), macular degeneration, reduced peripheral circulation, immune system
impairment, increased risk of heart disease – you name it.
Perhaps the most interesting component is that the sex hormones like testosterone and progesterone, as well as thyroid (which controls the rate at which those hormones are synthesized), oppose the glucocorticoids. With aging, you see a steady rise of glucocorticoids and a steady fall of thyroid and sex hormones. And with that you get steadily worsening body composition, health, and the accompanying rises in glucose and insulin levels (note: all this while eating LESS total food and FEWER carbohydrates).
Anyway, I could go on endless tangents here. But you should at least have recognized the greater complexity behind human metabolism than some stupid theory about carbohydrates causing a chronic elevation in insulin and glucose levels because of what happens in the hour that follows ingesting food. What happens in an hour after eating is pretty irrelevant in the grand scheme of things, especially over decades and generations.
Spiking insulin and glucose levels actually looks like it protects against insulin resistance, and can even reverse insulin resistance. This is all reminiscent of the good ol’ days when they thought that using your heart would cause it to wear out faster. Turns out that really stressing out your heart with some exercise just made the whole circulatory system stronger, and your heart go longer. I believe the same could be said with our glucose metabolism. You don’t develop superhuman glucose metabolism by avoiding carbs just like you don’t win races by sitting on the couch.
More on this in the next chapter, as we look at what could very well be the world’s most impressive documented case of insulin resistance reversal – and it happened not despite, but in part BECAUSE 250 grams of carbohydrates were added per day.
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