Foods high in bad fats, sugar and chemicals are directly linked to many negative emotions, whereas whole, natural foods rich in nutrients - foods such as fruits, vegetables, grains and legumes - contribute to greater energy and positive emotions.
Being in control of your life and having realistic expectations about your day-to-day challenges are the keys to stress management, which is perhaps the most important ingredient to living a happy, healthy and rewarding life.
I also think stress is related to control. When you're in charge of your life, you tend to not care about losing control of things that don't really matter like traffic jams.
I took anatomy classes. I went to medical libraries and talked to doctors and nutritionists. I did the whole thing before using myself as a human guinea pig.