Failure of the Calorie Equation

Thanks to various health classes, articles, and my own desire for everything to make sense, I’ve always believed the old equation that says calories in – calories out = change in weight. It’s simple. It’s easy to remember. It seems to be widely accepted.

It also provides an easy way to assign credit or blame for one’s weight. If you’re at a healthy weight, you must be doing the right things. If you’re overweight, you must be doing something wrong, and it’s your own fault for not being more disciplined. If you really wanted to, you would make the tough choices and eat better and exercise more.

However, that simple formula has a glaring problem that I tried to ignore or explain away for years:

It doesn’t work very well.

In the real world, most people want to be fairly healthy and maintain a good weight, but losing extra fat is difficult. Once lost, it’s extremely difficult to keep the weight off, and most people eventually fail and gain all of it back if not more. I doubt this is news to any of you. Having never struggled with my weight, I blew off this phenomenon as lack of discipline (“these people just aren’t respecting the equation!”), even though I knew how hard many of them fought and how much they watched their diets and how much they worked out.

A growing pile of evidence suggests that I’ve been wrong, that most of us have been wrong. Like it or not, metabolism isn’t nearly as simple as calories in vs. calories out.

The New York Times ran a fascinating article this week called The Fat Trap. I strongly recommend reading the entire article, but its main point is that your body actively resists weight loss and seeks to return you to your previous weight after you lose any significant amount. Once you reach a given weight, your body resets that weight as the ideal and tries to keep you there. Even if you do manage to lose some weight, you’ll have to work much harder to stay there permanently compared to someone who was already at the same weight, almost to the point that it becomes the primary focus of your life. Also, to make things even more difficult, people really do process food in different ways. In one study, given the same diet and same level of exercise, people lost or gained weight at different rates. That blows my mind. It also blows the equation out to the compost pile.

I’m no doctor or biochemist, but if true, this concept explains a lot. It makes me feel like a jerk for silently and ignorantly judging overweight people. It also makes me sympathize much more with those who do struggle with their weight. They not only fight the social stigma of being overweight and the difficult battle to eat better and be more active, but also their own bodies’ fighting against them.

Sure, there’s plenty of room for discussion about how and why we should prevent people from becoming overweight in the first place, which seems to be the only good solution. I’m working hard myself to stay trim, hoping to avoid a much more difficult battle 20 years from now. But for now, I merely want to open my own eyes, and maybe some of yours as well, to the nasty war that millions of people are fighting every day.