Why we get fat
Obesity and diabetes kill around 2 million people per year. It’s a problem with many causes, but I want to focus on two stories of what makes people gain fat.
Gary Taubes is a journalist with a science background, best known for his books Good Calories, Bad Calories and The Case Against Sugar, which blame carbs and specifically sugar for creating an internal hormonal milieu in which fat cells do not want to give up their energy stores. Hence, fattiness ensues.
This body-driven “endrocrine” hypothesis is at odds with Stephan Guyenet’s “brain-reward” theory of overeating, described in his book The Hungry Brain.
The two had a falling out a few years ago at the Ancestral Health Symposium, where Taubes publicly called Guyenet a sloppy scientist. Since then their disagreements have come to epitomize two different camps within the ancestral health community – those who are strictly low carb, and those who are not.
They recently sat down and argued for almost three hours on the Joe Rogan podcast, and neither one budged an inch. A listener could come away with only a sense of the overwhelming complexity of the topic, and just go back to eating junk food — wondering if it’s possible to know anything at all about what really causes obesity. This is unfortunate, because their mutual hatred stems largely from their egos, and they actually share a lot of common ground.
The Common Ground
Both Taubes and Guyenet agree that there is a mismatch between the environment in which humans evolved and the modern food landscape, and that this mismatch is responsible for the obesity epidemic.
The standard American diet (SAD) has all the ingredients to make it hard for people to expend more energy than they consume. It is high in refined carbs and sugar, as well as marginally-nutritional fats (or is that margirinally?), which deliver the one-two punch of the insulin spike (*knock knock*) to open cells up for a special delivery of high-density energy from fat calories.
Both Taubes and Guyenet also agree that chronically high insulin levels are a proximate cause of fat storage, but Guyenet wants to say that our brain wiring makes us continually crave food that spikes our insulin, while Taubes says the craving actually comes from the cell-signaling itself.
I tend to side with Taubes, in that we know that dramatic carbohydrate restriction is the single most effective weight loss intervention — if you can keep it. Brain-based personality and appetite changes that make us eat more, and more often, are downstream of dysfunction in the fat cells, but there may be complicated feedback effects that make it unclear what comes first — the food addiction or the endocrine disorder.
Guyenet’s work helps to explain why it’s so hard to break the cycle initially. Even though “good” calories, such as healthy animal fats, are highly satiating, they do not provide the same dopamine fix for someone addicted to highly palatable foods like donuts and soda.
There is a frustrating segment of the Joe Rogan debate, where the two talk past each other for several minutes on the question of whether sugar alone is enough to make you fat. I’ve written before about how high-carb, low-fat can be a viable weight maintenance, or even weight loss, strategy for people who are hormonally healthy. Indeed, in the context of a high-carb diet, increasing fat can be a major cause of insulin spikes.
You can still balance the ledger if you are able to balance energy intake and output by burning glucose as you consume sugar, but as soon as you add fat, the signaling changes and the sugar and fat will tend to go to the waistline. Taubes should accept this is evidence in favor of his endocrine hypothesis, but doesn’t because he wrote a bestselling book that makes sugar into a scapegoat.
Books like Salt Sugar Fat: How the Food Giants Hooked Us point out that the mixture of these ingredients would have been prized in our ancestral environment as a valuable store of energy to be used in times of scarcity. It would have signaled that “good times are here,” hence it both spikes insulin (to store energy as fat) and is highly sought after.
Given that modern humans can eat whatever they want all the time, the question for people who want to lose weight is: what will it be easier to give up most of the time? Sugar, or fat?
It’s harder to get important nutrients like Essential Fatty Acids on a high-carb diet, and easier to eat to satiety (without eating too much) if you opt for something like a ketogenic diet or low-carb paleo diet. I try to follow something closer to the latter.
The mistake doctors make in dealing with obese patients is telling them that they have to restrict calories beyond anyone’s reasonable willpower, when in fact many people could increase caloric intake and still lose weight if they are addressing the hormonal milieu that is keeping the body in fat storage mode, rather than fat burning mode.
Clearly there is more work to be done, but psychological research on food reward/addiction has to be synthesized with the physiological research on fat metabolism, endocrinology and nutrition. Real lives are on the line, and we can’t afford to tell or listen to only half of the story just because it strokes our egos or better fits our biases.