I wonder why the response to the recent report by the CDC--referenced by Peter below--has been to claim that it is good to be overweight, rather than to redefine what it means to be overweight. Surely if we place the prefix "over-" in front of an adjective, it implies that we’re talking about something that is excessive. Why would we even use the term "overweight," if not to mean that someone weighs more than one ought to?
This whole overweight crap was intended to increase the power of government over the people - and to secure the jobs of government nannys.
We need to start firing people responsible for crap like this.
The real problem is that there is no real standard for being "overweight." The guidelines that are seen most often were generated in the ’70’s, when Twiggy was all the rage. To give a personal example, I am 5’7" and 205lbs. By the current standard I am grossly overweight, even obese. However, I am also a runner and weightlifter. So, while my BMI may be in the stratosphere, I would warrant that my fitness level it much greater than someone significantly thinner and lighter than I. People do not, unfortunately, fit into easily definable categories. The media is really the one that drives these things. Their lack of true understanding about the science behind it, and the fact that it is an evolving and changing science, is the real problem.