Photo Credit: Public Health Image Library
Copyright: Nancy Clark MS RD CSSD August 2012
Protein for Athletes: What Do the Researchers Say?
Protein is a popular topic among both casual exercisers and competitive athletes, many of whom are confused about how much protein they need, when they should eat it, and the best kinds of protein to choose. The following article answers some of the questions active people commonly ask about protein in a sports diet. The information was presented by prominent protein researchers at the American College of Sports Medicine’s Annual Convention (May, 2012). The session was sponsored by P.I.N.E.S, a global network of Professionals In Nutrition for Exercise & Sport (www.PINESNutrition.org).
Do some athletes need more protein than others?
Just as children have high protein needs during growth periods (0.6 g Pro/lb; 1.3 g pro/kg), athletes also have requirements higher than the RDA (0.4 g pro/lb; 0.8 g pro/kg) when building muscles: 0.55 g/lb (1.2 g/kg) for endurance athletes and 0.75 g/lb (1.7 g/kg) for strength athletes. These protein recommendations assume the athlete is consuming adequate energy from carbohydrate and fat. Athletes who restrict their food intake end up using some protein for fuel, thus they need a higher protein intake. Most athletes consume ~0.7 g Pro/lb (1.6 g/kg/day), so they easily meet the protein recommendations—without supplements.
The biggest way to stimulate muscular growth is to lift weights or do other forms of resistance exercise. To support muscular development after hard lifting, all athletes need to consume high quality protein (with all the essential amino acids) in close proximity to their training. High quality proteins include milk products, poultry, eggs, fish, lean beef, all meats, and soy protein.
How should I spread my protein intake over the day? Is it better to have a large steak for dinner or smaller protein doses every few hours?
Many athletes eat very little protein for breakfast, but then feast on a high protein dinner. Current research suggests the trick to optimizing muscular development is to spread the protein intake evenly throughout the day. For example, if you were having a carbohydrate-based breakfast (such as oatmeal or a bagel) and a salad for lunch, you would be wise to include more protein in those meals. The goal is to consume at least 20 grams of protein every 3 to 4 hours. For example, a 200 lb (91kg) athlete who chooses at least 20 grams of protein per meal and snack will easily consume the recommended 150+ grams of high quality protein: 3 eggs for breakfast (21 g protein); 2 cheese sticks for a morning snack (14 g pro); 4 oz. deli meat in a lunchtime sandwich (28 g pro); an afternoon snack with 6 oz. Greek yogurt (18 g pro) mixed with 1/2 cup high protein cereal (6 g pro); a medium (6 oz). chicken breast for dinner (42 g pro); and 8 oz. cottage cheese (24 g pro) before bed easily does the job, with no need for protein supplements.
Are all dietary protein sources the same? What about supplements: whey vs. soy vs. casein?
Different types of proteins are comprised of differing amounts of essential amino acids (EAA) and have different rates of digestion. For example, whey is more rapidly absorbed than casein. Soy protein contains fewer EAA's than whey or casein. The EAA leucine is a key “trigger” for building muscle, so leucine-rich foods with rapid digestive properties are best for recovery from resistance exercise. Animal proteins—including plain or chocolate milk, lean beef, and tuna—are leucine-rich. Plant proteins contain leucine, but in lower amounts.
Because casein is slowly absorbed, consuming casein-rich foods before bedtime (such as cottage cheese) can help support muscle-building processes throughout the night. This may be particularly important for athletes seeking to maximize muscular growth during building seasons, such as during a pre-season training program.
Do other nutrients consumed at the same time as protein affect muscle recovery?
Yes. You want to enjoy carbohydrates in combination with protein. Carbs are important to refuel muscles, while protein's job is to build and repair muscles. Adding some fat, such as low fat or whole chocolate milk vs. fat free chocolate milk, also seems to increase protein uptake. Researchers are unsure why fat enhances protein uptake, so stay tuned!
Does adding protein to a sports drink enhance performance and/or recovery?
Studies suggest no improvement in either endurance or speed (time trial performance). The benefits of having protein in a sports drink relate more to recovery. Protein contributes to slightly higher muscle protein synthesis and glycogen replenishment.
Should I eat protein before exercise to promote post-exercise recovery?
Won’t hurt, but may not help. Eating 20 grams of protein 45 minutes before exercise increases amino acid uptake by the muscles to an equal extent as eating protein immediately after exercise. Take note: 20 grams of protein per recovery-dose is plenty. Athletes who consume higher amounts of protein either burn it for fuel or store it as fat.
When athletes lose weight, they also lose muscle. Is there a way to prevent that loss?
About 25 to 30 percent of weight loss relates to muscle loss. To abate this loss of lean tissue, dieters can 1) create just a small calorie deficit (as opposed to starving themselves with a crash diet), 2) choose protein-rich meals and snacks, and 3) include resistance exercise twice weekly in their training.
How should vegetarians - particularly vegans - meet their protein needs?
Vegan athletes can successfully meet their protein needs by eating a variety of plant foods. Most grains contain all 9 essential amino acids, just in lower amounts than an equivalent serving of animal foods. Hence, vegans need to consume generous portions of plant protein (grains, beans, legumes, nuts, soy) to compensate for both the lower density of the protein as well as the fact that plant proteins are less bioavailable (due to their fiber content).
The wisest way for a vegetarian to optimize protein intake is to consume adequate food. If the vegan is undereating, an energy deficit easily leads to muscle loss. Vegans who want to lose fat (not muscle) will want to focus their limited food intake on protein-rich plant foods. More tofu anyone?
Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes at her office in Newton, MA (617-795-1875). Her Sports Nutrition Guidebook and food guides for new runners, marathoners, and soccer players offer additional information. They are available at www.nancyclarkrd.com and sportsnutritionworkshop.com.