Protein is an essential macronutrient that is found in all human cells. Including additional protein in your diet can help you develop lean muscle mass. Protein alone, however, cannot induce muscle growth, but when combined with resistance exercise, protein synthesis can be maximised by ingesting specific types of protein in certain quantities and at strategic times, notes D.J. Weinert in the August 2009 issue of the "Journal of the Canadian Chiropractic Association".
The Institute of Medicine recommends the average person to take in 0.8 g of protein per kilogram of body weight daily as a minimum. However, the International Society of Sport Nutrition asserts that this minimum is inadequate for exercising individuals, who should take in between 1.4 and 2 g per kilogram of body weight daily. Strength-training athletes seeking to build muscle should aim toward the high end of this range. Men and women need the same amount of protein daily per kilogram of body weight when trying to build muscle, notes the "Oxygen" magazine website.
Although protein helps support muscle growth, eating pounds of steak at every meal is counterproductive. The body can only build ½ to 1 lb. of muscle per week, and this requires just an extra 10 to 14 g of protein per day. The body cannot store extra protein for later use -- it just gets used for energy or exits via the urine. The Institute of Medicine says that it is acceptable to eat as much as 35 percent of daily calories from protein sources.
Other nutrients are important to muscle development as well. When increasing your protein intake, make sure you still take in adequate amounts of carbohydrates which provide energy for workouts and muscle growth. Choose vegetables and whole grains for these carbs to obtain fiber and nutrients. Unsaturated fat, especially omega-3s, should also feature in your diet as they help with hormone production and provide extra calories to feed muscle growth, notes "Muscle and Fitness Magazine".
Types of Protein
Whole foods are the best sources of protein, according to the International Society of Sport Nutrition. Choose those with complete amino acid profiles, like meat, fish, and eggs. Complete proteins may also be made by combining incomplete sources like beans and rice or pasta and cheese, notes the IDEA Health and Fitness Association website. When whole food sources are unavailable or impractical, choose a supplement that contains both whey and casein, because they are highly absorbable and score highly in terms of amino acid availability, advises the International Society of Sport Nutrition.
Divide your protein intake up over the course of your meals to maximize absorption. The "Journal of the American Dietetic Association" published a study in September 2009 showing that eating more than 30 g of protein in any one sitting does not enhance muscle synthesis over 50 percent. So if you weigh 73 kg and need 145 g of protein per day, for example, try to eat a minimum of five meals with 29 g of protein at each. Having one of these meals around the time of your workout will help enhance muscle development and recovery, notes the International Society of Sport Nutrition. Have half of your meal prior to your workout and half afterward to supply protein during your workout and for post-workout growth and recovery.
- "Journal of the International Society of Sports Nutrition"; Position stand: protein and exercise; September 2007
- Institute of Medicine: Dietary reference intakes
- "Oxygen" Magazine: Power packed protein
- IDEA Health and Fitness Association: Protein quality, form and function
- "Journal of the American Dietetic Association"; A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects; T. Brock Symons, et al.; September 2009