January is peak diet season, and if it has you reaching for the latest weight-loss regimen, you’re not alone. But how do you know if that choice is just another crank diet?
Printed in the Washington Post, January 23, 2023, by Tamar Haspel:
Okay, so now maybe you’re thinking that, if those diets work, why write a whole column about their crankness?
Truth, justice and the American way, of course. But also maybe empowerment. Because people should know when they’re being sold a bill of goods.
Let’s look at some fun examples of diets that fit the crank model:
To be fair, there are a couple of diets that tell you flat-out they’re essentially a strategy to eat less. A primary rationale of the low-fat diet is that one 1 gram of fat has 9 calories and 1 gram of carbohydrate or protein has 4, so if you sub in more lower-calorie macronutrients, you consume fewer calories overall. And the Volumetrics diet posits that if you eat food that’s less calorie-dense, you end up consuming fewer calories.
While some diet rationales are pretty silly, they’re not all false. Insulin, for example, really does facilitate fat storage. But there’s one nutrition fact that trumps all the others, and it’s really the only thing you need to know about food and health: What we know is absolutely dwarfed by what we don’t know.
Remember the parable of the blind men and the elephant? Six blind men got to “see” an elephant by feeling a part of it, and they each came away with vastly different ideas of what an elephant was. The guy holding the tusk thought it was like a spear; the guy with the trunk thought it was like a snake. You get the idea. They came away with inaccurate ideas because they couldn’t feel the whole thing.
That’s what’s going on with diets. Nobody can see the whole elephant. Science hasn’t painted it (yet). So each diet guru latches onto some piece of human metabolism and decides that it’s the key to health and weight loss — but really, it’s just the toenail. Sure, digesting wheat yields polypeptides! But there’s so much else going on in the human body that it’s very hard to know how that plays out.
There’s one way to find out, of course: actual trials. And — surprise, surprise — the ones we have (and we have a lot) show that, long-term, no diet works for weight loss. The trajectory — subjects lose weight for a while, even up to two years, and then regain — is similar for all.
But let’s go back to that part where people actually lose weight on crank diets. Why is that? Because, after we peel back the sciency stuff, there are usually some pretty decent strategies for doing that thing that’s at the heart of weight loss — eating less.
So how about this: Ignore the sciency and cut right to the strategies. Sure, intermittent fasting doesn’t outperform other diets, but that doesn’t mean closing the kitchen after dinner is a bad idea. In fact, it’s a damn good idea.
Then look at low-carb. No, insulin doesn’t correlate cleanly with subsequent eating and weight gain, but that doesn’t mean cutting out sugar and refined grains is a bad idea. In fact, it’s a damn good idea.
To lose weight, you don’t have to understand the nitty-gritty of human metabolism; diet isn’t a knowing problem. You just have to figure out workable strategies to eat less; diet is a doing problem. So think of the onslaught of crank diets as a smorgasbord of strategies, and pick and choose the ones that can fit your lifestyle.
My hat is off to the people who are comfortable at whatever weight they are and focus on other aspects of their health. Unfortunately, I’m not one of them; being fat made me unhappy. And maybe that’s why the false hope that crank diets traffic in drives me nuts. But I also think weight loss is not just possible but completely straightforward — at least in principle.
It’s not a knowing problem, so forget about the polypeptides. It’s a doing problem, and only you know what to do.