Fat May Indeed Be Fattening

It’s a million-dollar question: What aspects of food make us more likely to pack on the pounds? Everything from saturated fat to food additives to sugar has been blamed for our obesity epidemic. Now we may have a better idea of what kind of diet contributes most to Buddha-belly, at least in rodents.

The journal Cell Metabolism published research in 2018 showing that mice piled on more weight when fed a relatively high-fat diet than they did when they ate other diets, including those rich in protein or—surprise, surprise—sugar.

The scientists fed mice a series of 29 specialized diets with varying amounts and forms of carbohydrates, fat and protein. The fat-rich diets changed the expression of brain genes associated with reward-seeking, prompting the rodents to feast on more calories than they needed—out of pure joy.

Before you overflow your breakfast bowl with sugary boxed cereal, remember the study was conducted on mice. We’re not sure how the findings apply to human metabolism. Determining optimal human diets often bumps into ethical concerns. After all, scientists can’t subject people to drastic diets for several years in a controlled environment, hoping that some will get fatter or sicker than others. Still, the results suggest it may be wise to go easy on the butter and not drown your greens in oil.