Proteins give your body the power to build new tissues and fluids among other functions. Your body cannot store extra protein so it burns it for energy or converts it to fat. The amount of protein you need depends, in part, on your:
Good sources of protein include meat, cheese, eggs, and nuts
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- Level of fitness. Physically active people need more protein than those who do not exercise. You also need more protein when you start an exercise program.
- Exercise type, intensity, and duration. Endurance athletes often burn protein for fuel, as do bodybuilders and other athletes who perform intense strength-building activities.
- Total daily calories. Your body burns more protein if you do not consume enough calories to maintain your body weight. This can happen if you eat too little or exercise too much.
- Carbohydrate intake. Your body may use protein for energy if you exercise with low levels of muscle glycogen or if you do repeated training sessions without eating more carbohydrates. When you start with enough muscle glycogen, protein supplies about 5% of your energy; otherwise, it may supply up to 10%.