How Much Protein Do We Really Need?
Q. How much protein do we need and do we need to focus on concentrated sources of protein (protein powders, bars, supplements, etc) to get in enough?
This question was posed to me in regard to someone who is 220 lbs and engaging in regular weightlifting several times a week for several hours and besides focusing on consuming high protein foods, was adding in 100 grams of protein 2x a day. In addition, they were curious as to what happens to any excess protein.
In general, according to the National Academy of Sciences, Institute of Medicine,
"The Recommended Dietary Allowance (RDA) for both men and women is 0.80 g of good quality protein/kg body weight/d and is based on careful analysis of available nitrogen balance studies."
So, for someone who is 220 lbs, 220 lbs is 100 kgs. 100 x .8 - 80 grams of protein/day. For those who are involved in higher levels of strength training, they may need a little more, even up to 1.25 to 1.5 grams/kg as recommended in the American Dietitic Association position paper on the topic;
"Protein recommendations for endurance and strength-trained athletes range from 1.2 to 1.7 g/kg body weight per day."
This would be the equivalent of 120 to 150 grams of total protein.
However, the key here, and one that is often overlooked, is to evaluate the amount of protein their regular diet is contributing.
Someone who weighs 220 lbs and is engaging in the level of activity mentioned, will need about 3000 calories per day or more. The average American diet is about 15-20% protein which means that from their diet alone, this person would be getting about 115 to 150 grams of protein.
And this is exactly what the ADA position papers says...
"These recommended protein intakes can generally be met through diet alone, without the use of protein or amino acid supplements."
So, in the situation above, their regular diet alone would provide more than enough protein and no extra protein would need to be consumed. Adding in 100 grams of protein 2x a day would bring the total protein to 315 to 350 grams per day, which is way more than excessive.
As you can see, the focus on "getting enough" protein, even in athletes, is often misplaced, as most are getting in more than enough protein from their diet. This is where the focus should be, to get our protein, and all of our nutrients, from our regular diets. To do so, focus on high quality protein foods that are also low in fat, saturated fat and cholesterol such as beans, lentils and peas.
Now, in regard to your question about what happens to the excess protein, the body does not store excess protein and therefore must eliminate it. Over time, excessive amounts of protein can potentially put a strain on the kidneys, liver and our bones. In addition, excess protein can raise the levels of a hormone called IGF-1, which may stimulate the growth rate of certain cancers.
So, I would consider the above situation protein overload and as we see, this person would easily get enough protein from their regular diet and that is where the focus should be.