Senior author Mark Friedman of the Monell Chemical Senses Center in Philadelphia said triglycerides are a form of fat that is transported in the blood and stored in the body's fat tissues.

The global obesity epidemic is thought to be caused in part by consumption of a diet high in fat and carbohydrates, which promotes weight gain. This propensity to gain weight is at least partially controlled by genes, with some individuals gaining more than others eating the same diet, Friedman said.

The study, published in the International Journal of Obesity, screened rats for vulnerability to diet-induced obesity by measuring the increase in blood triglyceride levels following a single high-fat meal. The rats were then fed a diet high in fat over the next four weeks.

The researchers successfully predicted which rats became obese over the four-week period by examining the earlier metabolic response to the high-fat meal -- the smaller the triglyceride change, the greater the weight gain.