Protein - How much is enough?

Protein is one of the major biomolecules found in food, along with carbohydrates (discussed in an earlier blog post) and fats/lipids. Protein is primarily used to create and repair body tissue - such as muscles. The common thought among most gym-goers is that more protein is better. It is not unusual to see "gym rats" wolfing down protein shakes, protein bars, piles of chicken breasts and egg whites galore. Many people wishing to increase their muscle mass believe that they too must consume inordinately large amounts of protein just like the pro bodybuilders do, if they have any hope of achieving their goals. It's not unusual to hear people suggesting that protein intake should be in the range of 200-300 grams per day! Just how much protein is enough?

The recommended dietary allowance for protein for the average adult is 0.8 grams (g) per kilogram (kg) of bodyweight. If you know your weight in pounds, multiply by 0.45 to convert it to kilograms. For example, if you weigh 160 lbs, then your weight in kilograms is approximately 72 kg. For the average adult with this bodyweight, your recommended dietary allowance for protein would be 57.6 g per day. Typically, 15% to 30% of the calories in your diet should come from protein (each gram of protein yields 4 calories).

For those individuals who are active recreational athletes, your protein recommendations are somewhat higher. The minimum acceptable intake would be 1.0 g per kg of bodyweight - but most who are athletically active should aim for somewhere in the range of 1.2 to 1.8 g per kg of bodyweight.

For those individuals who are bodybuilders or seeking to increase muscle mass, again the minimum acceptable intake is 1.0 g per kg of bodyweight - but should aim for a protein intake in the range of 1.6 to 2.0 g per kg of bodyweight.

For those individuals who are endurance athletes (such as marathon runners and triathletes), the minimum acceptable intake is 1.4 g per kg of bodyweight - but should aim for a protein intake in the range of 1.6 to 2.0 g per kg of bodyweight.

If protein is used for building tissue such as muscle, should it not make sense to just consume as much as possible? The answer is no - going above the maximum of the ranges listed above do not have any scientifically proven benefit to add additional muscle or improve athletic performance. High protein diets require increased water consumption, since protein need 7 times the water for metabolism than carbs and fats. Also, those who follow high protein diets often consume less than the recommended amount of carbs - and since carbs are vital for creating glycogen and energy, the result can be energy loss and slower metabolism. Scientific studies have shown that consuming excess protein above what is needed for tissue maintenance causes the body to excrete calcium, which is an important mineral for keeping bones strong. Lastly, there is a limit on how much protein your body can convert into tissue at a point in time - if you consume large amounts well in excess of that limit, your body will end up storing the calories as unwanted body fat.