Fat A long-term storage form for energy in humans. It is also one of the three main nutrients in food (besides carbohydrates and proteins). Foods high in fat include butter, oil, nuts, and some dairy products. Related Articles: How to Read the New Food LabelAn Overview of Intermittent Fasting7 Tips for Healthy Eating While Working from Home10 Low-Carb Foods to Strengthen Your Immune SystemSouth Asian Diets and Diabetes