By now you've probably seen or heard the headlines that fitness trumps obesity when it comes to risk factors for early death.
Businessweek had a pretty good look at the study.
The short version is that if you are obese, but fit, you're better off than if you are obese but not fit. Also, if you are obese but fit, your risk factors/chances of early death aren't that much different than a non-obese person.
Naturally, there are some upsides and downsides to the study that determined this.
- The study broke out the effects of fitness on obese people. So if you're fit and strong but obese, you are better off than just being obese.
- It was a large (40,000 people) and long (1979 - 2003) study.
- they measured body fat with calipers and/or water immersion, not with BMI. BMI is meant for a population rating, and it doesn't tell you anything about the body composition of the individual. Caliper body fat checking and water immersion body fat analysis do.
- it showed that being significantly underweight isn't that healthy, either.
Study's Downsides There are a few downsides to the study:
- it was partly sponsored by the Coca-Cola company. While this doesn't impugn the work of the researchers, it does color how people will view the results. Coca-Cola has a vested interested in dispelling ideas that your obesity affects your health, as sugary drinks are connected to expanding waistlines.
- While it studied 40,000 U.S. adults, they were "mostly Caucasian, male and well educated" - a relatively narrow group. This might be useful scientifically (it reduces the variations from sex, ethnic background, and education/wealth) it means that the results are harder to extrapolate to the general population.
- based on a questionnaire, at least partly - this always raises questions about honesty and accuracy of answers. Even an honest answer might be incorrect, since it's anecdotal.
- even those classified as healthy by the study may have had one serious risk factor. This means the number of healthy people cited includes people who have some kind of issue, albeit less issues than those classified as unhealthy.
So it's not all clear-cut. But it does mean there is a real benefit to getting out there and moving, even if your weight doesn't come down as much as you'd like in the process. Still, there is no reason to be complacent if you're obese. You're just not as bad off as the scientific consensus once held.