The problem with studies

Last week we learned, after all of this time hearing how fat is killing us, that if you are overweight but not obese, you actually may live longer than the thin person. How is it, most of us ask, that we can be preached at about excess weight for years, only to now find out that a little extra insulation on your frame ain't necessarily all that bad? Well, there are a couple of reasons.

First, researchers go into these studies with a theory. In this case, the theory is "fat is bad." It's funny, but when you go into a study looking to prove it, you usually do. Yes, there is peer review, but when most of your peers are of the same mindset, it isn't that hard to slip some weaknesses by them.

Second, the Body Mass Index (BMI) is nice as a general stat, but its weakness is its inflexibility. People are built on variety of frames. Some are also more muscular than others. This means a person with a larger frame and/or extra muscle are going to show up as overweight, even if they are not. It is the garbage in garbage out theory. Many of these weight studies are working with cookie cutter definitions of "over weight" when in fact people are built very different from one another. The data is therefore weak from the start.

Finally, there may or may not be extra factors that play into this, but which are very difficult to calculate. For instance, are in shape, thin people bigger risk takers than slightly overweight people? If so, overweight people may still be more susceptible to diseases like diabetes or heart disease, but have slightly longer life spans than thinner people who take unnecessary risks. I don't know that the previous is true, but the problem is that the authors' of these studies don't know either.

Studies have to be taken with a grain of salt. They make nice guide lines for your health, but at the same time, you can't live by them.