It's true that protein satisfies hunger in a way that fats and carbohydrates can't — possibly one reason why high protein, low-carb diets are popular.
Protein has a second quality that may be equally important to people who are losing weight. One of protein's amino acids, leucine, appears to be the key to preserving muscle while losing fat, say researchers at the University of Illinois. Other studies show that leucine can promote muscle building when overall calories are low.
To get plenty of leucine from protein and still avoid the animal fat in meat, consider these low-fat, leucine-rich protein sources:
1/2 cup firm tofu, 1,511 mg. leucine
1/2 cup low-fat cottage cheese, 1,440 mg. leucine
8 ounces fat-free milk, 818 mg. leucine
1 ounce reduced-fat mozzarella cheese, 670 mg. leucine
1 ounce reduced fat cheddar cheese, 608 mg. leucine
Hard-boiled or soft-boiled egg, 538 mg. leucine
1 cup coucous, cooked, 464 mg. leucine