Calories Count!

Updated 5.20.2012**; reformatted 9.4.2015
Carson C. Chow is interviewed in the NY Times He looked at gaining weight mathematically, trying to figure out why a third of Americans are overweight. Human metabolism can now be modeled accurately, he says. I've used his model to measure the number of calories needed to lose weight over time, the link is at the end of this piece.s

Here's the abstract to Chow's talk:

Accurate predictions of how much weight individuals will gain given their daily food consumption and physical activity can now be made using validated mathematical models of human metabolism. Models can also be used to dispel some myths about weight gain and weight loss. The dynamics at the individual level can be extended to the entire population of a nation. Applying such a calculation to the United States has shown that the increase in per capita food supply is more than sufficient to explain the obesity epidemic.

In other words, we are fat because we produce too much food. Wait, what? Producing too much food doesn't make you fat. Eating too much food makes you fat.

But his contention is that when presented with more food, people will eat more food. But... no one is required or forced to eat more food. Or to have more food in their homes. Or to clean their plates at a restaurant. That is a function of personal choice. All of that said, I know first hand how hard it can be to not eat something placed on the table.

The way to solve that problem is to send the extra food away, and certainly do not have it in your house.

But most people eat out more often than in previous generations, and that is related to lower food prices, eating out is more accessible. It's very easy to ingest thousands more calories than you realize if you buy processed food or eat at restaurants.

Genetics, Chow said can play a role, but if food is not plentiful, susceptible people don't get obese. So you can't blame genes; if you stop bending your elbow you will lose weight. Physical activity he claims isn't that much less than it used to be. Not sure I agree with that statement. Certainly people had desk jobs in the 1970s and 1960s too and were not as fat, but I don't think they sat at screens for as long in the evening.

His work shows that it takes a year to stabilize at a new weight— which no one trying to lose weight wants to hear. He does not say if speed of weight loss affects the length of the stabilization period. The bottom line is that all diets work, and some can work fast, but then you have to remain with an adjusted intake. Therein lies the real difficulty.

But there is evidence that metabolisms recovery, especially if regular exercise is included in the maintenance period. Which is why it's eat and move more. Because the moving more helps fight against the natural down shift in metabolism as intake is lowered and the body seeks to re-establish equilibrium (homeostasis).

Another Chow quote:

And when you're obese, it's not like we can suddenly cut your food off and you'll go back to not being obese. You've been programmed to eat more.

Here I would quibble, I don't think you have to be obese to struggle to retrain (or to use his word reprogram) your body to be satisfied with fewer calories. I think people of all sizes can struggle with this, but obese people perhaps more so because in order to maintain their large size they have to eat large quantities of food. To break that cycle means consciously forgoing something that you enjoy.

And that's what insidious about the problem. It develops over time. Most people don't begin by eating over 4000 per day, but work up to that total over time. It's very easy to add 200-300 extra calories to your diet without feeling like a glutton.

That's also why the constant snacking model for losing weight is so insidious. Humans do not need to feed continuously, but the brain and body will adjust to that schedule. As with any habit, that's tough to break.

Here is the interactive version of their model, which I have found helpful when trying to re-orient my own thinking about how much I should be eating (total calories): bwsimulator.niddk.nih.gov

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**This date is an estimate of the original publication date. The file as originally published had no date on it.

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