1. As I recall, the topic first came up long ago in relation to getting longer lifespans. 2. These studies are NOT studies on reducing overweight or reducing obesity. Trim is fine. Trim usually improves health. The longevity studies with caloric restriction actually take the individuals down to an intake long term that almost just manages to be starvation level. It's a very tricky thing to do. Caloric restriction studies take the caloric intake down to BELOW maintenance levels long term. (The body adjusts as long as starvation levels are not reached and as long as the diet is very, very, very carefully balanced.) Individuals who are on these diets do not get just trim; instead they tend to be extremely thin. Sometimes getting quite thin is also done for other health reasons after the fact, for example, the reduction in pressure from fat in the abdomen can help some men with enlarged prostates to urinate, and certainly there are those with circulatory problems and other woes whose physicians want them thin. ***Even those people are NOT on the strict level used for the caloric restriction studies done to see if longevity can be altered, though.*** So far, that kind of extreme approach seems to work best in certain invertebrates with very mixed results in vertebrates. 3. There was a report on this in Science News, too, which came out last night: <http://www.sciencenews.org/index/generic/activity/view/id/343374/title/Low-cal_longevity_questioned> That mentions in more detail that some malignancy rate reduction can be seen individuals who begin caloric restriction early BUT those individuals have problems, too, even when experts are designing the diet: QUOTE None of the monkeys that were started on calorie restriction early on has developed cancer, she notes, compared with six monkeys in the standard-diet group. But calorie restriction very early in life may come with risk. Some monkeys started very early on calorie restriction developed diabetes, even though they are far from obese, she says, and some show signs that their immune systems might not be as good as those in the control animals. QUOTE Decades of research have linked low-calorie diets with extended survival, but a new report finds that rhesus monkeys on strict diets don't live longer than their counterparts getting a standard diet. END QUOTE That is consistent with the mouse studies which also have very mixed results. The whys for the mixed results are what need to be uncovered. There are multiple possibilities from the levels of caloric restriction, the balance and components of the diet, and more. END QUOTE 4. Yes, being trim is often associated with high amounts of exercise and study after study after study has found that staying active is at or near the top of the list for being healthy. What needs to be taken home from this is that although a number of invertebrates benefit from such extreme diets with longer life spans, the results with diets as extreme as those used in the longevity studies are very mixed with multiple vertebrates, and there can be downsides for vertebrates like increased risks of diabetes and damaged immune systems beyond NOT being able to design such a diet to be safe without experts creating the diet and constant monitoring, as well as constant hunger and needing to learn to sew to get clothing that fits, or even doing brain damage if the diet is not balanced right. Those downsides might also be there for other mammals like ferrets. Again, remember, these studies are NOT about just being trim, which is known to usually be more healthy. The diets and weights in this situation are much more extreme. Sukie (not a vet) Ferrets make the world a game. Recommended ferret health links: http://pets.groups.yahoo.com/group/ferrethealth/ http://ferrethealth.org/archive/ http://www.miamiferret.org/ http://www.ferrethealth.msu.edu/ http://www.ferretcongress.org/ http://www.trifl.org/index.shtml http://homepage.mac.com/sukie/sukiesferretlinks.html all ferret topics: http://listserv.ferretmailinglist.org/archives/ferret-search.html "All hail the procrastinators for they shall rule the world tomorrow." (2010, Steve Crandall) A nation is as free as the least within it. [Posted in FML 7534]