Overeating foods rich in saturated—but not polyunsaturated—fat boosts liver fat, which can lead to liver damage and may raise the risk of type 2 diabetes.

In a recent study, Swedish researchers randomly assigned 60 people with overweight or obesity to gain roughly five pounds by adding muffins made with either a saturated fat (palm oil) or a polyunsaturated fat (sunflower oil) to their usual diets.

After eight weeks, liver fat increased by 53 percent in those who ate the muffins made with palm oil, but not at all in those who ate the muffins made with sunflower oil. What’s more, an enzyme that can signal early liver damage rose only in those who ate the palm-oil muffins (although it remained in its normal range).

What to do

Replace most saturated fats with unsaturated fats. Though this study used only palm oil, an earlier study reported similar results with a mix of three saturated fats: coconut oil, butter, and blue cheese.

Photo: mythja.