For years, protein was placed on a pedestal and touted as the ultimate performance food. Athletes and bodybuilders used it to bulk up, while others looked to the high-protein, low-carb formula of diets like Atkins and The Zone to slim down. The result? While many Americans still don't get the protein their bodies need, others are eating too much. It's important to know that what's right for you depends upon your size and the amount and type of exercise you do.
Protein is an essential nutrient composed of amino acids. There are 22 amino acids, categorized as essential (those that must be obtained from food) and nonessential (produced by the body). In the body, the amino acids are involved in the formation of enzymes, hormones, and muscle protein; they provide structure to the skeleton and boost the immune system to keep us well. Protein can also serve as an energy source during exercise, contributing 5 percent of calories when enough carbohydrate is consumed and up to 15 percent if the intensity of exercise is high enough or when calorie intake is inadequate.
The body digests protein to form amino acids, part of an amino acid pool that also contains those from body proteins. When enough protein is consumed, the body is able to synthesize new proteins from the amino acid pool. If protein intake is shortchanged, protein breakdown exceeds protein synthesis, resulting in a decrease in muscle size and strength—which will negatively affect workouts. So what are the requirements?
Type Of Person - Grams Protein/Pound of Body Weight
Sedentary adult 0.4
Three-days-a-week exerciser 0.5-0.75
Competitive adult athlete 0.6-0.9
Teenage athlete 0.9-1.0
Athlete trying to gain mass 0.7-0.9
Athlete trying to lose weight 0.7-1.0
Maximum usable amount for an adult 1.0
For the average 150-lb. person who exercises three days a week, the daily dose of protein translates into 75 to 112.5 g. Eating a 4-ounce chicken breast alone provides 35 g. Just remember that each gram of protein contains 4 calories. So if you opt for one of these high-protein diets, some of the excess will be used for energy, but the rest may be stored as fat.