[Content warning: weight and calorie numbers.]

I have a lot of sympathy for intuitive eating, a strategy in which you respond to your inner body cues about food. For instance, you eat when you’re hungry, and you stop when you’re full; if you feel a craving for avocados or cheese or celery or bread, you eat the thing you’re craving; at each meal, you ask yourself “hmm, what sounds good?” and then eat that.

A point in favor of intuitive eating is that people are naturally absurdly good at regulating their own eating. Now, I know that some people are going to the comments to go “obesity epidemic! Obesity epidemic!”, but think about the facts. A weight gain of 11 pounds over six months– a remarkably quick rate of weight gain– only requires a one percent mismatch between your energy expenditure and your consumption of food. (This fact I got from Nutrition: A Very Short Introduction.) Most people– even overweight or obese people– have a stable weight, naturally eating about as much as they burn; even people who gain weight typically gain it relatively slowly, as the product of a tiny difference between their energy expenditure and food consumption. This is a truly remarkably effective system.

On the other hand, intuitive eating is expecting a lot of your body’s signals.

I can imagine about four ways that food self-regulation can work.

First, there’s the way that water works for me. Most of the time, water is vaguely unappetizing. When I’m thirsty, water is suddenly the MOST DELICIOUS SUBSTANCE IN THE UNIVERSE, until I’ve had a glass or two, at which point it mysteriously transforms back into being vaguely unappetizing. If I drink water when it is vaguely unappetizing (which I’ve done under the instruction of gym teachers), it sloshes around in my stomach and I feel uncomfortable. My body is capable of correctly indicating when I’m deficient in an important nutrient (water) and creating a plan to no longer be deficient.

Second, there’s the way that pica works. When people feel a craving to chew ice, it’s often a sign of deficiency in certain minerals, particularly iron, even though ice doesn’t contain any iron. A desire to chew ice is a fairly reliable indicator of a mineral deficiency, but chewing ice will not give you any minerals. In this case, my body is capable of correctly indicating when I’m deficient in an important nutrient, but it does not create a viable plan to no longer be deficient.

Third, there’s the way that B vitamin deficiency worked for me. When I first became vegan, I didn’t take a B vitamin supplement. I felt fine, but I mysteriously acquired this sore near the side of my mouth that wouldn’t go away. I shrugged it off until a horrified friend said, “you have a serious B vitamin deficiency! Get a B-complex NOW!” In this situation, my body did not indicate that I was deficient for months after I was seriously deficient.

(Although now that I think about it I did have bizarre near-sexual cravings for cheese, so maybe my body was indicating it and I didn’t listen.)

Fourth, there’s the way that sweet things work for me. While my body does eventually tell me it no longer wants to eat sweet things, it tells me that well after a nutritionist would have said “maybe you should eat fewer Tootsie Rolls.” In this situation, my body drives me to eat a particular nutrient (sugar) even though I am not remotely deficient in it and in fact I am probably consuming an excessive amount. Presumably, this is because Tootsie Rolls did not exist in the environment of evolutionary adaptedness and thus there was no need to fear excessive sugar consumption.

So I think the question about whether intuitive eating is a good idea probably depends on which of the four kinds of food self-regulation is the most common (either for people in general or for a specific person). If most things work like water, then intuitive eating works great. If most things work like pica, then intuitive eating is still a good idea, but requires a little more thought and care. If most things work like B vitamins or sweet things, then intuitive eating is probably a bad idea.