If you are feeling down and need a little mood booster, have a few carbs. Don't go overboard or eat carbs loaded with sugar, we are talking about only 30 grams of carbs. That is all it takes to give a boost to your serotonin levels. Try 4 cups air-popped popcorn, 1/2 cup oatmeal, or half a whole-grain English muffin with just a tablespoon of jam and/or peanut butter. Carbs have gotten a bad rap. Eat good carbs and don't overdo it!