Good question. So I had to google the subject! Here's what I found: http://www.ajcn.org/cgi/content/abstract/62/4/746 http://www.betterhealthandliving.com/articles/how_long_will_you_live http://www.eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=EJ442525&ERICExtSearch_SearchType_0=no&accno=EJ442525 http://www.thirdage.com/long-life-tips/living-to-100-centenarians-show-us-how In general, cenetarians are NOT fat...as in overweight fat. From the first link: "Despite such differences, fat-free mass (FFM) and resting metabolic rate (RMR) were not different in centenarians compared with aged subjects but were lower than in adult subjects. In contrast, healthy centenarians had a waist-hip ratio (WHR) lower than that of aged subjects but not different from that of the adult subjects." It would appear that there are a number of factors which go into such a long, healthy life...not the least of which is diet and lifestyle. Genetics also plays a significant part in this. Thyroid activity, for example, is one example of a genetic influence. I found a couple links (included above) which compared dietary patterns: One said cenetarians consumed breakfast more regularly, avoided weight loss diets and large fluctuation in body weight, consumed slightly more vegetables, and were less likely to consume low-fat diets and to comply with certain nutritional guidelines. Another said, under "Watch Your Diet": Emphasize fruits and vegatables, whole grains, figer, and polyunsaturated fats; avoid cholesterol, saturated and hydrogenater fat; and more. It would seem that, with some variety in conclusions apparent, that there must be factors other than simple diet and exercise which account for this...like the genetics. Having known people who have reached advanced ages, I rather suspect that there are also certain physiological changes which occur during the aging process which result in the tendency to slim the body down. I can remember Aunts and Uncles, for example, who were much bigger when I was a child who are now nowhere near the size they used to be. And they have made no conscious changes in their diets, other than to cut out things they can no longer tolerate, for example. This was a good question!