Inbred C57BL/6J mice have been used to study diet-induced obesity and the consequential physiological effects associated with it. Little is understood about predictive factors that predispose an animal to weight gain. To address this, mice were fed a high fat diet, control diet or normal chow diet. High fat diet fed mice exhibited a large amount of variation in body weights between the mice at the conclusion of the diet protocol. This variation is not present in obese leptin deficient mice, which have less variation in body weight. Several measurements including pre-diet serum hormone levels and pre-diet body weight were analyzed, but had no predictive value regarding weight gain. However, weight loss response due to food deprivation showed a strong positive correlation with high fat diet induced weight gain. These data suggest that adolescent fasting induced weight loss is a useful predictor of diet-induced weight gain.