Calories in and calories out

Teen Obesity: lack of exercise may not be to blame — Time Magazine.

Here’s the logic:

Based on two studies about 20 years a part, American teens today are getting about the same amount of exercise as they did in 1991. Yet obesity has shot up 30% since 1976. What gives?

Weight is all about calories in and calories out. If calories out has stayed pretty much the same, then it must be about calories in.

… even small changes in a person’s energy balance can have a significant effect on weight. Studies have shown that eating just 10 to 20 extra calories per day — that’s one peanut M&M or one tortilla chip — that don’t get burned through activity can result in a 2-lb. gain on average over the course of a year.

So the teasing headline was never much of a mystery. It is only ever about calories, in or out.

Sure, kids are taking more on board now than ever before, thus the gain, but after all the education why are they no better in taking it off?

Slightly more than a third of American kids today meet federal physical activity recommendations, which call for activity strenuous enough to cause heavy breathing for a total of an hour a day for five or more days a week.

So the vexing question remains: if it’s simply an either/or, calories in or out, why has this supremely simple equation so badly befuddles us for so many years? It just isn’t that hard to understand.