Chocolate's a great pick-me-up, but which kind gives your brain the biggest boost? Scientists at Wheeling Jesuit University compared dark chocolate, milk chocolate and carob and found that milk chocolate provided the most improvement in concentration, response time and recall of words and images on computerized tests. (Thank the extra sugar.) For a quick mental performance booster, try 85 grams—about two chocolate bars—15 minutes before a test or any time you need a little extra focus.

Dark Chocolate Antioxidants fight heart disease, and several stimulants, including caffeine and theobromine, enhance brain activity for brief periods.

Milk Chocolate Low in antioxidant power, but stimulants plus sugar get your brain moving fast.

White Chocolate No cocoa color means no antioxidants. Fat and sugar add sweetness and empty calories.

Carob Low-fat, high-fiber, sugar- and caffeine-free. But zero antioxidants.

• 18 Servings (2 cookies per serving)
• Prep Time: 30 Minutes
• Baking Time: 11 Minutes

• 1 cup margarine
• ½ cup brown sugar, packed
• ½ cup sugar
• 1 egg
• 2 egg whites
• 1 teaspoon vanilla extract
• ¼ teaspoon salt
• 2 cups unbleached flour
• 1 teaspoon baking soda
• 1 12 ounce bag of semisweet chocolate chips
• ¼ cup chopped walnuts (optional)

Preheat oven to 350°F. Cream margarine, brown sugar and white sugar in a large bowl. Beat with an electric mixer until smooth. Add egg, egg whites, vanilla and salt, and beat well.

In a smaller bowl, combine flour and baking soda. Slowly add mixture into the larger bowl, and beat with electric mixer until batter is smooth and creamy. Fold in the entire bag of chocolate chips, and add walnuts if you like. Drop dough by large teaspoons onto a greased cookie sheet, then bake for about 11 minutes.

Walnuts are chock-full of omega-3's and add bulk to your cookies, helping you feel full faster. Substituting margarine for butter can provide healthier fats.