Is a fat metabolite the major diet dependent accelerator of aging?

Previous work with a high fat/low carbohydrate diet indicated that Drosophila melanogaster aged faster on that diet than on a high carbohydrate/low fat diet. This could be due to one of eight possibilities enumerated. Oxygen consumption of flies on the high fat/low carbohydrate diet is initially the same as that on the control diet. Subsequently the oxygen consumption falls to below control levels at older ages. No increased rate of living is indicated. A starvation resistant strain is described. The male eats less food, and yet maintains a body fat level indistinguishable from the parent strain. The lifespan and most physiological indices of aging used indicate that the process of aging is unchanged. Nutrient dilution produces a nearly compensatory increase in food intake with a reduced body fat and body energy reserves. The indices of aging used indicate that the rate of aging is reduced under these circumstances. These results are consistent with the possibility that fat or a fat metabolite alters the rate of aging. It is argued from previous data that body fat itself is not likely to be the important factor, rather a metabolite is probably involved.