Recently I wrote about carbohydrates, fats, and protein, the major sources of energy in our diet. Getting sufficient amounts of these nutrients is essential to promote good health and exercise performance. Given the current trend of low-carbohydrate diets and an emphasis on protein for everything from fitness to weight loss, many people have wondered about how much protein they should eat. This is the topic of my Health & Fitness column in the Aiken Standard this week.
As you might expect, protein needs vary from person to person for a variety of reasons. For example, an athlete who is working out to add muscle or training for a triathlon needs more protein than a person who does less strenuous exercise. Despite these individualized protein needs, there are some broad recommendations that apply to most people.
There are two ways to estimate the amount of protein a person needs, both of which you may be familiar with. One is to recommend a certain amount of protein, in grams, based on body weight. The RDA, the amount that meets the needs of almost all healthy adults, is 0.8 grams of protein per kilogram of body weight (g/kg) per day. You can calculate your protein requirement by multiplying your body weight by 0.4, so a 200 lb. person would require about 80 g protein per day. (You can also use an online calculator, like this one)
Meeting this protein requirement isn’t very difficult. A four-ounce serving of meat contains about 30 grams of protein, an egg has 6 grams, and a cup of milk has 8 grams. Plants contain protein, too—whole grain bread and cereal has about 4 grams per serving, and one cup of cooked beans contains about 15 g. Getting enough protein is important, but there is little benefit to eating more protein than you need and excessive intake could cause health problems.
In general, most adults get enough protein but children, women who are pregnant, and older adults should make an extra effort to eat protein-rich foods. Vegetarians and vegans, especially athletes, need to carefully plan meals to get enough protein and the right balance of amino acids to meet health and performance requirements.
The other way to estimate protein needs is based on the number of calories you eat. According to the Institute of Medicine, the acceptable range for protein is between 10–35% of total calories. If you eat 2,000 calories each day, this would equal 50 to 175 grams of protein each day. For someone who weighs 200 lbs, this would be between 0.5 and 2.0 grams of protein per kilogram. Notice that the RDA fits within this range, which accounts for the protein requirements of nearly everyone, including people who have very high protein needs.
While the RDA is sufficient for most healthy people, even those who exercise regularly, it may be too low for athletes engaged in strenuous endurance or strength training. The protein requirement for endurance athletes, including runners, cyclists, and triathletes, is 1.2–1.4 g/kg per day. Athletes who are training to add muscle mass and strength—think football players in the offseason—need even more protein: 1.2–1.7 g/kg per day. This should meet both energy needs to fuel training sessions and provide adequate protein for muscle repair and growth.
For most of us, though, the focus should not be on eating more protein but to get our protein from healthy sources. For starters, several servings of protein-rich lean meat, eggs, and dairy as well as whole grains, legumes, and vegetables should meet protein needs. The emphasis should be on real food rather than processed foods with added protein. After all, no amount of granola bars with added protein will make you healthier!
Nutrition, exercise, and health information can be confusing. But it doesn't have to be that way. What can I help you with? firstname.lastname@example.org | http://twitter.com/drbrianparr