Turkey and mashed potatoes need not be reserved for Thanksgiving, thanks to the mood-boosting vitamins and minerals this main dish and savory starch contain. Potatoes are complex carbohydrates, and eating them actually increases production of serotonin. That's why ingesting complex carbs helps people calm down, even when they're feeling stressed or overwhelmed (as many of us do during the holidays) [source: Magee]. Turkey is also credited with being one of the top feel-good foods because it contains many nutrients that stave off depression and maintain good moods. Because turkey can make people feel sleepy (it packs a mighty wallop of tryptophan), try serving iron-rich spinach or other leafy greens on the side to provide a much-needed energy boost.