I considered posting this in biology, but think this needs broader dissemination, having appeared in Science and all. I've been saying this for years, but never realized I could get published in Science for it! I'm seriously questioning the quality of that journal to consider this cutting edge research. (No, this isn't a joke.) Science, Vol 307, Issue 5709, 584-586 , 28 January 2005 Full article: http://www.sciencemag.org/cgi/content/full/307/5709/584 So, there you have it, according to Science, lean people don't sit on their butt as much as obese people. I'm sure you're all relieved to know it's no longer idle speculation, and the official results are in.