【原文】 Eating a balanced diet is still the best nutritional strategy for maintaining energy. A "balanced" diet means that you've combined different types of wholesome foods in each of your small meals to obtain a healthy proportion of the macronutrients - protein (lean beef, poultry, fish, eggs or low fat dairy), carbohydrates (whole grains, fruits and vegetables) and fats (nuts and seeds, fish oil, olive oil, canola oil, flaxseed oil). They're all important because each macronutrient serves a different role in keeping energy constant. Protein is required for growth and repair of virtually every tissue in your body and serves an important role in the production of brain chemicals called neurotransmitters that influence energy. Carbohydrates are your muscles' and brain's preferred source of fuel, and fats are used in the creation of cell membranes and hormone-like substances called eicosanoids that help regulate heart rate, blood pressure blood vessel constriction and the nervous system. Fats also moderate digestion to make you feel full longer.