In a German study, participants added to their normal diets a daily serving of low-fat yogurt mixed with lard, butterfat, rapeseed oil or olive oil. Those who ate the olive oil yogurt had a higher concentration of serotonin, a hormone that makes us feel satiated, in their blood. Here’s where it gets really interesting: In a follow-up study, the researchers gave participants either plain yogurt or yogurt mixed with olive oil extracts—that is, just the compounds that give olive oil its aroma. The people who ate the yogurt that smelled like olive oil ate 176 fewer calories per day. Try adding a splash of olive oil to your meal to feel fuller and eat less!