As I mentioned recently, knowing the math behind something doesn’t necessarily mean that your behaviour will change.  Still, this article is a really neat look at how some smart nerds created a mathematic model to predict weight gain based on some general inputs.  They further modeled the root cause of why obesity is such a crushing problem today.  They concluded that the main reason isn’t a sudden lack of activity in the last 30 years, but rather the relatively sudden overabundance of food, most of it bad for you. 

In the 1950s, when I was growing up, people rarely ate out. Today, Americans dine out — with these large restaurant portions and oil-saturated foods — about five times a week.

Right. Society has changed a lot. With such a huge food supply, food marketing got better and restaurants got cheaper. The low cost of food fueled the growth of the fast-food industry. If food were expensive, you couldn’t have fast food.

People think that the epidemic has to be caused by genetics or that physical activity has gone down. Yet levels of physical activity have not really changed in the past 30 years. As for the genetic argument, yes, there are people who are genetically disposed to obesity, but if they live in societies where there isn’t a lot of food, they don’t get obese. For them, and for us, it’s supply that’s the issue.

For my money, you never ignore the math nerds, sure there are problems with modeling, but man it’s compelling stuff overall.  They link to a super cool java Body Weight Simulator that is fun to play with too.  For me the most interesting bit of the article was this:

…the conventional wisdom of 3,500 calories less is what it takes to lose a pound of weight is wrong. The body changes as you lose. Interestingly, we also found that the fatter you get, the easier it is to gain weight. An extra 10 calories a day puts more weight onto an obese person than on a thinner one.