Our aim is to define how repeated starvation affects the biology, physiology and molecular biology of organism, by using C.elegans. Adult worms were exposed to two cycles of 6hr starvation-18hr feeding diet pattern, and their fat accumulation was analyzed by Nile Red staining and biochemical quantification. The expression of genes involved in fat synthesis (
pod-2,
fasn-1,
mboa-2,
sbp-1) and fat degradation (
hosl-1,
lipl-4,
cpt-1,
cpt-2, B03003.3, F53a2.7) in the worms were also determined by real-time RT-PCR. Both fluorescent analysis and biochemical quantification showed that fat content of worms experienced repeated starvation increased. There was no obvious change in the expression of genes involved in fat synthesis, but those of fat degradation tended to decrease, which is consistent with the increment of fat in worms experienced repeated starvation. The life span, fecundity and mobility of worms experienced repeated starvation did not show differences compared to those of the control worms. Our results indicate that repeated starvation causes metabolic and nutritional effect on organism. It is often mentioned that repeated, and often unsuccessful, dieting leads to weight regaining of all or more than initial loss, which is referred as rebound weight gain. However, it is difficult to know whether such weight gain is caused by metabolic and/or genetic alteration. Our data in worms may provide a molecular basis of rebound weight gain.