Cooking peanuts breaks open the tiny protective shells around the fat inside, making it easier for your body’s digestive juices to reach and break down the fat.

When you cook peanuts, your body can absorb more of the fat inside them, so you get more energy from the same amount of peanuts — mice that ate cooked peanuts gained more weight than those that ate raw ones, even when they ate the same amount.

Crushing peanuts into butter doesn’t help your body get more energy from them — only cooking does. Mice that ate blended peanuts gained the same amount of weight as those that ate whole ones, even though the nuts were crushed.