A Conversation Between Gary Taubes and Gretchen Rubin
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A Conversation between Gary Taubes and Gretchen Rubin A Note from Gretchen Rubin: On September 30, 2016, Gary Taubes and I talked by phone for a few hours about his new book The Case Against Sugar. I’m a huge fan of Gary’s work. As I describe in Better Than Before, my book about habit change, while on vacation in March 2012, I read Gary’s book Why We Get Fat and overnight, I changed practically everything about the way I ate. I call this form of habit change the “Strategy of the Lightning Bolt”; Gary’s ideas hit me with the force of the lightning bolt, and my habits changed effortlessly. I asked him to do this interview because I want to highlight key points from his book The Case Against Sugar. The book contains so many crucial arguments that it can be challenging for the reader to keep track of them all. I want to help other readers experience the same lightning-bolt of understanding that has so benefitted me. Onward and upward—to better health. -- Gretchen Rubin GretchenRubin.com 1 Gretchen: Hi Gary, thanks for doing this. Your work includes so many important points and so many mind-blowing conclusions that as the readers, we can lose track as we go. I wanted to have this conversation to underscore the points that stand out, to me, as really key. To start with the bottom line: If we’re looking for the factor at the heart of all our escalating health problems, one factor explains it. And that’s sugar. Gary: Yes. We’ve got these epidemics worldwide of obesity, diabetes and the chronic diseases associate with them, which are the diseases likely to kill us. These epidemics show up in different rates in different places. They began in the 19th century in the U.S. and Europe, and then late in the 20th century or mid-20th century among North America populations and Inuit populations, in the South Pacific and the Middle East. Everywhere you look in the world, as populations become westernized, they manifest obesity and diabetes sometimes in almost unbelievable rates. Gretchen: It’s extraordinary to see the consistency of this pattern Gary: “Occam’s razor” is the principle that we should never complicate a hypothesis beyond necessity, but rather start with the simplest possible hypothesis to explain an observation. Here, the simplest explanation is sugar. When you add the combination of fructose and glucose—what sugar is—to any baseline diet, the end result is obesity and diabetes. To sugar, I would add refined grains, which is the phenomenon I wrote about in Good Calories, Bad Calories, but some populations—in Southeast Asia in particular—had already been consuming significant grains. But they don’t show these negative effects until you add sugar to that diet. Once you add sugar, you get obesity and diabetes. Without sugar you don’t have it, or at least not at the rates that are detectible in the population. Gretchen: Take us through the key consequences of sugar. Gary: First, let’s step back for a moment and clarify what we mean by “sugar,” because that’s been a point of confusion in this story for over a century. So when I say “sugar” in the context of what we eat—i.e., not “blood sugar”—I mean both sucrose (the white, powdered stuff we put in our coffee) or high-fructose corn syrup. The two are both composed of simpler carbohydrates, roughly 50-50 combinations of glucose and fructose. And our body deals with them both pretty much in the same way. When you eat grains or starches, they break down upon digestion into glucose alone, which is absorbed into your blood stream pretty quickly. That’s what stimulates insulin secretion from the pancreas, and you get elevated levels of insulin for the next few hours after consumption. (In fact, you start getting insulin secretion before you even eat, just thinking about consumption, but that’s not that relevant at the moment.) GretchenRubin.com 2 Sugar has glucose in it, but it also has this fructose, which is what makes it so sweet, and the fructose mostly gets metabolized in the liver. When you consume sugar—both the fructose and the glucose together—as you do if you drink a soda or fruit juice or eat a sugar-sweetened cereal, you’re getting the effect of both these carbohydrates together. Even when you eat fruit, you’re getting fructose with glucose, so you’re always going to metabolize that fructose in the liver in the environment of the elevated blood sugar and insulin that comes about because of the glucose. Now, the fructose in this high glucose/high insulin environment appears to cause a condition called insulin resistance, first in the liver and then throughout the body. And this insulin resistance phenomenon is absolutely key to understanding both obesity and diabetes. Gretchen: Then is it really the fructose that’s triggering the insulin resistance, or is it the combination? Gary: Well, you always see the glucose and fructose in combination. So you can argue that because glucose alone may be relatively harmless, that the problem is the fructose. But since we always consume the fructose with the glucose, that’s an assumption. What we know, or at least what I think we know, is that the two together in sugar are a problem. Gretchen: Could you eat only glucose? Gary: Yes, if you eat a high starch diet, or high carb, high grain diet, such as in Southeast Asia. For poor Southeast Asians, if most calories come from rice, they’re getting most of their calories from glucose with very little or no fructose. Gretchen: So is it more accurate to say that eating glucose and fructose in combination leads to insulin resistance? Gary: Yes. Gretchen: And insulin resistance is a key aspect of metabolic syndrome? Gary: Yes. The CDC now says that about 75 million Americans have metabolic syndrome and so are at high risk for diabetes, heart disease, and even cancer. Metabolic syndrome is defined by a cluster of what could be called metabolic abnormalities, starting with the fact that you’re probably getting fatter. High blood pressure is a sign of metabolic syndrome, as is low HDL cholesterol (i.e., the “good” cholesterol), and high triglycerides (blood fats) and a tendency to have high blood sugar. All those GretchenRubin.com 3 things tend to go together, plus fat accumulation—your waist is getting bigger. And all of that goes under the diagnosis of metabolic syndrome At the heart of it is this insulin resistance phenomenon. If you aren’t insulin resistant, you’re not going to be diagnosed with metabolic syndrome. As it happens, it’s tough for physicians to test specifically for insulin resistance. You have to do the test in the doctor’s office and it takes time. Your doctor can’t just take a blood sample and send it off to the lab. The other tests that can be done quickly: your doctor can weigh you, measure your waist circumference, and take your blood pressure. Your doctor can take a blood sample to measure HDL and triglycerides, and all this is quick and easy. And if the results are not where they’re supposed to be, these are all signs that the patient is insulin resistant. Although your doctor will tell you that you have metabolic syndrome. Gretchen: Insulin resistance is the gateway to all of the negative consequences? Gary: Yes, they come together. Of course, the ultimate manifestation of this is type 2 diabetes. Without insulin resistance, there’s no type 2 diabetes. You can see the insulin resistance before you’re a type 2 diabetic, but type 2 diabetes seems to be fundamentally a disorder of insulin resistance. Gretchen: Is it accurate to say that these effects are very much tied to the act of consuming sugar? I mean, if you don’t consume that sugar, then you’re not going to trigger this cascade of effects? If so, then it’s within our power to avoid those consequences. Gary: It gets tricky. True, sugar is the initial trigger of all of this but, say, if your mother consumed sugar while she was young and then pregnant with you, and she became insulin resistant, with all its sequelae—well, you’re likely to be born insulin resistant even if you’re now living in a sugar-free or low-sugar environment. Gretchen: Wow. Gary: You’re going to manifest insulin resistance even without sugar in the diet, and you become metabolically compromised. Removing sugar might not be enough—and probably isn’t enough—to re-set the insulin resistance. You’d need to remove all the carbs. That’s the next step, and that’s where it really gets complicated, and where people tend to get confused. It’s also where a lot of the pushback comes against this way of thinking. GretchenRubin.com 4 People who argue that we should eat very low-carb, very low-sugar, high-fat diets in order to be healthy—or who argue that obese and diabetic individuals should eat very low carb, very low sugar, high fat diets in order to be healthy—are probably right. Nevertheless, that doesn’t mean that all carbs cause the metabolic syndrome. I’d say that initially it was caused by the addition of sugar to the population, and its trickle- down effect from generation to generation. When you look at how to fix it, you go to this next step, where you now need to remove sugar as well as much or even all of the carbohydrates in the diet and replace them with mostly fats, or at least healthier sources of carbohydrates—green leafy vegetables, for instance, instead of grains.