Saturated fat intake may influence the expression of a person's genetic obesity risk, according to a recent study.

Researchers from the Jean Mayer USDA Human Nutrition Research Center on Aging Tufts University in Massachusetts found that limiting saturated fat could help people whose genetic make-up increases their chance of being obese. A person's genetic risk for obesity is linked with Body Mass Index (BMI) and saturated fat intake may influence the expression of their genetic obesity risk.

"We already know there are certain genes that interact with dietary fat and affect BMI," José M. Ordovás, senior author of the study and director of the Nutrition and Genomics Laboratory at the USDA HNRCA at Tufts University, said in a statement. "In the current study, we analyzed dozens of variants of those genes and other genes frequently associated with obesity risk and saw that, while total fat intake was related to higher BMI, people who were genetically predisposed to obesity and ate the most saturated fat had the highest BMIs."

For the study, researchers identified 63 gene variants related to obesity and used them to calculate a genetic risk score for obesity for more than 2,800 white, American men and women enrolled in two large studies on heart disease prevention.

They found that people with a higher genetic risk score, who also consumed more of their calories as saturated fat, were more likely to have a higher Body Mass Index (BMI), the ratio of body weight to height.

Ordovás and colleagues hypothesize that people who have these gene variants that predispose them to obesity may be more sensitive to saturated fat, which is found mostly in fatty cuts of meats, including beef and pork, as well as butter, cheese and other high-fat dairy products.

"Little is known about the mechanisms that might explain the role of saturated fat intake in obesity," Ordovás said. "Some clinical models suggest that saturated fat might interfere with activity in the part of the brain that lets us know we're full, in addition to a few studies in people that suggest a diet high in saturated fat interferes with satiety. More research is needed to know whether those findings would also apply to gene function."

He added that genetic risk score could be useful in identifying people who are predisposed to obesity and could ultimately lead to personalized dietary recommendation.

"If further research can clarify a relationship between obesity related genes and saturated fat, people with higher scores would have even more incentive to follow advice to limit their saturated fat intake as part of an obesity prevention strategy," Ordovás said.

The findings were recently published in the Journal of the Academy of Nutrition and Dietetics.