Let’s be clear: You absolutely, positively can lose weight on a crank diet. If you have lost weight on a diet eliminating fat, or carbs, or gluten, or plants, or meat, or sugar, you’re not alone. But the dirty little secret is that, if you’ve lost weight at all, it’s because you’ve found a way to eat fewer calories than you expend. Eliminating categories of food is one way to do that. A good way, for lots of people, at least for a while.
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:
- The grain-free diet, a la “Wheat Belly,” holds that wheat digestion yields polypeptides that bind with opioid receptors in the brain, which makes wheat an appetite stimulant.
- The carnivore diet claims to decrease hormonal fluctuations, because the insulin spikes associated with carbohydrates create a “cascade of other imbalances” of hormones associated with hunger and fat storage.
- Intermittent fasting holds that restricting intake for an extended period of time gives your body no choice but to tap fat stores, so you lose more than if your body has continuous access to blood sugar.
- The blood type diet says that your blood type tells you your ancestry, and we thrive on the food our ancestors ate. And there are plenty of other ancestral diets that double down on this idea.
- And of course low-carb/keto, which holds that, because insulin is key to fat storage, if you don’t eat carbs, you don’t release insulin and you store less fat.
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.
I’ve been overweight, but I’m not now, and I’ve used ideas from different diets to keep it that way. I don’t do intermittent fasting, but I close the kitchen after dinner and put off breakfast until I’m quite hungry. I don’t follow a low-fat diet but limit added fats in dishes I make. I’m not low-carb, but I don’t eat many refined grains. I bulk up dishes with vegetables (Volumetrics). I eat almost no ultra-processed foods (every diet known to man). I don’t keep easy-to-eat foods that call to me in the house (common sense), and when we have to buy Girl Scout cookies for neighborhood harmony, I make my husband stash them somewhere (okay, nobody recommends that, but it works for me because Thin Mints call my name).
What I hate most about crank diets is that they prey on people who want, often desperately, to make a change. The metabolic rationales offer a lifeline — all I have to do is this one thing! — and then the ultimate failure feels like your failure. But anyone who’s ever tried it knows that weight loss is hard. There is no one thing. And only you know where your diet goes off the rails, which foods are your undoing, how changes fit, or don’t, in your life.
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.