Whey

Muscle in your body is constantly being built up and broken down. That makes whey protein an excellent food to consider. Whey comes from the liquid that remains after milk has been processed into cheese, and there are very good reasons why it's so popular with body builders. In one study, published in the International Journal of Sport Nutrition and Exercise Metabolism, whey not only increased muscle more than casein (the protein found in cheese), but also contributed to loss of body fat.

But whey can do a lot more than help you build healthy muscles. It can help you build a healthy immune system and boost your metabolism, thereby helping to keep your mood upbeat and sunny. Simply put, its whey cool!

You can pick up whey at any health food store. Blend it into your favorite shakes or mix it into an eight-ounce glass of milk. You can also find lots of recipes online for other tasty beverages.