The average breakdown of the Mediterranean diet: 50 percent carbs, 20 percent protein and 30 percent fat. But they're eating predominately unsaturated fat from olive oil, olives and nuts -- not the unhealthy saturated and trans fats you find in pizza and processed foods. And here's the thing about saturated fat: studies have shown that it tricks you into eating more food, because it messes with your hunger hormones. On the flip side, unsaturated fats can help control insulin (the hormone that helps your body use sugar efficiently).

In addition to eating plenty of healthy fats, they get their carbs from whole grains and fruits, and their protein source is typically legumes and seafood. They do eat meat, but infrequently.