Weight Loss Is Math, Sort Of

The traditional view of weight loss is that it's simple math: "calories in, calories out" or, more specifically, you need to burn off 3500 calories more than you consume to lose one pound.

But everyone knows that this isn't strictly true. If it were, it wouldn't be so hard to lose those last 10 pounds, and certain very disciplined dieters (often female) wouldn't lose weight more slowly than their slacker counterparts (often male).

Age, genetics, hormones, and muscle mass play important roles in weight loss. Even more important are changes in society (how we grow and distribute food, how and where we eat) and our individual relationships with food (particularly whether we routinely use food to manage stress and anxiety).

A recent profile of Carson C. Chow, a mathematician at the National Institute of Diabetes, Digestive Diseases, and Kidney Diseases offers a new spin on this issue: weight loss is math, but maybe less like arithmetic and more like A.P. calculus.

Using mathematical modeling, Chow demonstrates what people who have lost weight and maintained that weight loss know: it's a much slower and less linear process than the "3500 calories= one pound" theory would have us believe. He says, for example, that reducing calories by 100 per day (that's a large apple!) will result in a loss of 10 pounds in three years.

This--along with Chow's other conclusions: that we need to change farming practices and stop marketing food to children--are unlikely to hit the bestseller lists or make headlines. But as a clinician in practice, I can tell you that when I see a middle aged person who's lost 10 pounds in three years it is a rare and remarkable event.

I recently had the opportunity to write a book that includes stories contributed by women over 50 who have lost weight and improved physical fitness. These stories support Chow's "slow dieting" concept. Most of the women made small changes and then sustained them over years. Interestingly, most of the changes were tied, in some way, to deepening a relationship: a couple walking together, a mother and daughter cooking together, and so forth.

And my patient who eats "almost nothing?" I encouraged her to eat a little more, move a little more, and adjust her expectations.