Wednesday, March 24, 2010

Princeton Study: All Calories Are NOT The Same

"High-fructose corn syrup causes characteristics of obesity in rats: Increased body weight, body fat and triglyceride levels", published in Pharmacology Biochemistry and Behavior, doi: 10.1016/j.pbb.2010.02.012:

In Experiment 1, male Sprague–Dawley rats were maintained for short term (8 weeks) on (1) 12 h/day of 8% HFCS, (2) 12 h/day 10% sucrose, (3) 24 h/day HFCS, all with ad libitum rodent chow, or (4) ad libitum chow alone. Rats with 12-h access to HFCS gained significantly more body weight than animals given equal access to 10% sucrose, even though they consumed the same number of total calories, but fewer calories from HFCS than sucrose.
Although the article aims directly at the difference between High Fructose Corn Syrup (HFCS) and sucrose or a sucrose/glucose mixture, I don't want to address that.

I want to point out that this result completely invalidates "Calories In, Calories Out" (aka "if you're fat you're either lazy or undisciplined or both") as a diet meme. This study shows definitively that HFCS calories are different in the body than sucrose calories.

OK, that was a bit hyperbolic. But let's look at a couple of facts:
  • Calories In, Calories Out doesn't work (studies variously show that as few as 6% of people who diet actually lose weight long term -- any system that fails that often can't be described as "working"). Google "effectiveness of dieting" for, like, half a million articles.
  • There is science showing that people can eat 7000 calories a day and not gain weight and people can eat 700 calories a day and gain weight. No, I'm not going to explain it. Go read Gary Taubes' "Good Calories, Bad Calories". All of it. You can get a copy from Amazon for $10 or so.
We know that the human body is a complex system. Even if the Calories In, Calories Out people didn't mean "how much you eat, how much you exercise" and instead meant "the net caloric input from food accounting for incomplete processing and the complex systems of energy storage within the human body minus the net caloric output resulting from biochemical production of energy within the body and its systems" they'd still be telling us something relatively useless, because behavioural changes based upon diet and exercise just don't work very well (see that "effectiveness of dieting" search again).

What this study does is show definitively that what you put into your body matters as much as how much you put into your body. As an example, I lose weight when I stop eating carbs and eat beef. Lots of beef. More calories of beef than I ate of carbs. I suspect that has something to do with my body not digesting all the beef I eat, or having to spend more energy on converting beef to useful energy, or something. I don't really care.

Research like this will eventually tell us (and the answers for different people will be different) more flexible ways to eat and exercise while maintaining an appropriate weight if we choose to do so. Right now there are a lot of people who'd like to do that who can't manage to do so. Accepting that "Calories In, Calories Out" is too simplistic will be helpful, and the more complete understanding of the homeostatic system that we call the human body will gradually help more and more of us.