Yogurt is definitely one of my "go-to" snacks. It's convenient, tasty, good before a workout, and packed with calcium and protein. Of course, I'm talking about non-fat, unflavored yogurt - just add your own fruit to avoid the excessive sugar load of the many flavored varieties. I just learned yet another reason to love yogurt; it is loaded with tyrosine.

You may not be familiar with tyrosine so let me fill you in on some details - it is an amino acid that converts into the feel-good chemicals dopamine and adrenaline (in small doses adrenaline is a good thing). These chemicals help keep your brain clear when you are under stress and also provide a much needed energy boost. It takes anywhere from 200 mg to 2000 mg of tyrosine to feel calmly energized. Reach for an 8 ounce cup of plain low-fat yogurt for 656 mg of tyrosine, or 1/3 cup of dried soy nuts which has 850 mg of amino acid, or take 1/4 cup of Parmesan cheese and melt it on some whole grain bread for a whopping 1,314 mg.

If you have time, I'd go for the Parmesan melt, but for convenience I'll take some yogurt.