Outliers: This lean is mean

Outliers is sure you know one. They never have to diet, they eat as much or more than you, and yet they stay skinny with little effort. Now researchers have found what gives them an edge.

A study published in the American Journal of Physiology-Endocrinology and Metabolism finds that those lucky people genetically have “poor fuel economy,” meaning they burn more calories while exercising than people who have “fat” genes.

“This has implications for how we consider metabolism when attempting to prevent or treat obesity,” said the research team led by Chaitanya K. Gavini of the School of Biomedical Sciences at Kent State University. “Targeting pathways maximizing skeletal muscle energy use during physical activity may take advantage of already existing mechanisms that are endogenously employed to a greater extent in naturally lean people.”

In a study of rats that all had similar weight and lean body mass, those with stronger aerobic capacity were more active. But the kicker was, while both types of rats burned the same amount of calories while at rest, those with the “skinny” genes expended a lot more energy (and calories) during mild exercise.