So where are all these fit but fat people...

Via Jane Galt comes this new republic article about how being fat isn't an issue if you are fit (bugmenot - that there is a lot of research that people who are overwieght but physically active do better than people who are thin but not physically active. Jane's take is that the difference is that it's hard for someone who isn't in shape to exersize, so they are less likely to be active.

I think that's true. But I think it goes further than that. Weight is a pretty good proxy for fitness level. I go to the gym pretty regularly (although not as often as I would like to). Almost everyone there (except me) is in really good physical condition. While I know plenty of people who are skinny/normal body types who don't work out regularly, I know of few grossly overweight people who do. So while it may be true that being fat isn't necessarily bad for you if you are physically active, it seems to me like it's difficult to be physically active and fat. In fact, I've noticed that, in my own struggle with the gut, there have been times where I've pretty much gone crazy eating but kept exersizing, and my weight pretty much stayed the same.

The same applies to BMI. It's not perfect, but it's still a pretty good indicator of weight. Sure, you can throw some unusually muscular people into it and come up that they are obese, but for the vast majority of people - people whose extra weight comes from eating a box of pizza rolls for dinner chased down by a pint of Chubby Hubby (my regular dinner in my pre-diet days) rather than from spending hours lifting weights - it can provide a reasonable guide for where you are and where you need to be closer to. (For the record, my bmi is 25.8, so I'm still overweight, but not by as much as my gut would suggest...)

The TNR article also points out that there are studies showing that mice put on low calorie diets gain it back once they go off the diets and resume eating an amount that they were eating before, and that the same thing happens in humans. That means that crash diets are a bad idea, but it doesn't mean that changing your eating habits is a bad idea. My guess is most people who are overweight/obese are eating way more calories than they expend. Increasing physical activity is one way to eliminate those calories, but so is decreasing the amount consumed - not bringing it down to a crash diet amount, but instead by cutting out enough calories to bring it below the amount expended. That doesn't mean getting rid of the occasional treat, but it does mean not eating a gallon of pudding as a midmorning snack. Part of the trick to losing weight and keeping it off is to not go on a crash diet, but instead to develop healty eating habits - habits that are healthy enough for you to lose/maintain weight, but that are palatable enough that you can keep them for life.

So while I think there is some merit in the "fat but fit" argument - especially in the importance of regular exersize - I think that there are few people that are truly fit but are still fat - that fat is a good indicator/signaling mechanisim of fitness.