I'm back again fighting the battle against my weight, cholesterol and blood pressure. As a guy who tries to be very rational and very scientific, I'm constantly looking for (and constantly frustrated) by the lack of rigorous and useful scientific data that guides me in trying to change my behavior to have a better health outcome. In doing this, I am frequently frustrated.
For instance, when I was a kid, we were warned about eating to much sugar. Sugar, it was said was the major cause of hyperactivity and tooth decay. In fact, both of those appear to be myths. Parents have been told that their kids will be more hyper when they've had sugar, and often apply a purely subjective standard for their children's behavior depending upon whether they know if they've had sugar or not. And of course pure sugar is relatively less of a problem than starchy carbohydrates because tooth decay is primariy caused by a bacteria which feeds on sticky starch which remains stuck to teeth, which causes them to emit acids which attack tooth enamel.
By the late seventies, the blame had shifted to dietary fats. It seems logical: if you are getting fat, it's probably, well, because you ate too much fat. So, a huge industry began which fed America based upon this wisdom: we saw the creation of larger and larger amounts of "low-fat" and "non-fat" foods, which we as Americans bought in vast quantities. And, the net result of all this was that obesity rates skyrocketed. In other words, when millions of Americans did what experts told them to do and lower their fat content, they became fatter and fatter, and dramatically so.
The Atkin "revolution" told us that much of what we learned was a lie: that in fact it wasn't fat which made us fat, it was carbohydrates. Our new demon was bread: you could eat all the steak you wanted, as long as you didn't eat any of that bread.
The fact of all of this is that food metabolism is very complex, and much of what people say about diet is not only incorrect, but in fact can't possibly be correct. As a for instance, the conventional wisdom is that "a calorie is a calorie". It doesn't matter if you eat fats or carbs or proteins, it all doesn't matter. If you have an excess of around 3500 calories, you will put on a pound of fat.
But this can't possibly be true. Let's say that it were true, and you were one of those lucky people who "hasn't gained a pound since college" (let's say that's 10 years ago). That means that in the span of 3653 days (we'll round), your total caloric intake as compared with your energy expected has to be balanced to within 3500 calories. That requires a precision of about one calorie per day. I burn a calorie in a few seconds of walking on a treadmill. Does that make any sense to anyone?
There obviously has to be more at work here.
I got on this track courtesy of Jay Parkinson's blog. He's an MD, and was writing about a retailer who pulled a T-shirt from their stores which carried the message "Eat Less". He said that he thought it was a bad thing, because anorexia accounted for a mere 1% of the population, while 35% of us were obese. According to figures provided by UN FAO (and linked by Parkinson) Americans consume on average 3790 calories per day. The American Heart Association suggests that I eat between 2000 and 2400 calories as a moderately active adult male in my age group. Let's say that my activity level burns 2200 calories per day, but that I am one of these "average" Americans. This means that I am overeating to the tune of 1590 calories per day. I should put on more than a pound every three days. If weight gain (and loss) were really as simple as Parkinson would have you believe, the real question isn't "why can't I seem to get thin" but rather "why aren't we all bursting our skins?"
Someone left this link to a talk by Gary Taubes on Jay's discussion board. I think it's pretty interesting, and points out some of these fallacies and the likely causes. I think that if I could internalize some of the lessons, it might prove to be helpful.