Protein and Exercise

by Matthew Kadey

For the longest time, protein was an afterthought, and carbohydrates and fat got all of the attention with respect to human health. However, advances in research have found that consuming adequate amounts of protein, especially that of high quality, can promote optimal wellness and vitality. Recent popularity of diets including Atkins and South Beach has propelled protein into the forefront. While there are a significant number of flaws in these dietary programs, they do serve one important purpose: getting people thinking about protein.

Types of Protein

Protein is found in a vast array of foods. However, certain foods contain protein that is considered to be of a superior quality. For example, the protein found in a chicken breast is of higher quality than the protein found in pasta. Protein quality is measured by how it promotes net protein balance within the human body and is a function of the amount of essential amino acids (cannot be produced by the body) that it contains. For omnivores, the top protein sources would be items such as chicken, fish, red meat, eggs and dairy. As for non animal eaters (e.g., vegans), top quality protein could come from soy (especially fermented soy) and hemp. What is important is that one’s diet consists of a variety of high quality protein sources throughout the day.

Protein and Health

Nutritional recommendations define the primary use of amino acids as substrates for synthesis of body proteins. However, there is emerging evidence that additional metabolic roles for some amino acids require plasma and intracellular levels above minimum needs for protein synthesis.

Enzymes, hormones, skeletal muscle, bones and hair - these are just a sample of substances that contain protein. Thus, to function properly, we need to eat some protein. For example, it was once believed that excess protein could be detrimental to bone health by creating an acid environment that would leach calcium from the bones. While it is true that for some people the excess intake of proteins (especially from animal sources) can take a toll on skeletal strength, it is also true the consumption of adequate protein in the diet is essential to bone strength and thus, reduces the risk of osteoporosis.

Some of the most interesting research regarding protein is its impact on body weight. Protein’s ability to increase satiety and therefore decrease caloric intake is one mechanism behind this outcome. Therefore, if you were to eat the equivalent in calories of chicken versus white pasta, you will likely be hitting the fridge sooner after the bowl of pasta. High-fat junk food (especially if it is low in fibre) may be the least filling of them all.

Another way protein may help with the battle of the bulge is in its ability to increase thermogenesis (calorie burning) in comparison to carbohydrates and fat. New research shows that carbohydrates, fat and protein all act differently in our bodies, proving that calorie counting is more complicated than simple addition. Protein has a higher thermic effect of feeding (TEF) than the two other macronutrients and therefore uses up more calories during digestion. One particular amino acid, leucine, has been found to turn up the body’s heat. Interestingly, one of the best dietary sources of leucine comes from a properly processed whey protein supplement. While the TEF of protein is about twice that of carbs or fat, the overall contribution of TEF to total calories expended is likely to be somewhat small.

Keep in mind that one of the main reasons why high-protein, low-carbohydrate diets result in rapid weight loss is due simply to the large reduction in calories. Take away the pasta from the pasta with meat sauce, and you are sure to create a calorie imbalance.

How Much Protein Do We Need?

The standard recommendation for protein intake for the average person is 0.8 grams of protein per kilogram per day. However, this recommendation is impractical considering that the vast majority of people in well fed societies consume well over this amount. For example, this level is only 64 grams of protein for an 80 kilogram person. It is also not nearly enough for anyone who exercises regularly. Basically, only a truly sedentary person could get away with such a small amount. Peter Lemon has for a number of years been at the forefront of protein research when it comes to exercise, and through various studies, he has determined the following:

  • Individuals engaging in regular endurance type exercise should aim for about 1.2-1.5 grams of protein per kilogram of body weight per day.
  • Individuals engaging in regular resistance training should aim for about 1.4-1.8 grams of protein per kilogram of body weight.
  • Those involved in both types of exercise on a regular basis (e.g., hockey and basketball players) will likely need the most total protein. However, if an athlete is consuming well over 2,000 calories per day, there should be no problem getting enough total protein even without any supplementation. A bigger concern is making sure they are getting enough high-quality protein and not making up calories with nutritionally devoid food.

One also needs to keep in mind the fact that different people have different metabolic needs. Some of us (like this author) seem to function particularly well on a high-carbohydrate diet while others do better living like the cavemen. Therefore, simply saying that there are set protein guidelines would be much too presumptuous. See Noah Hittner’s Q&A titled “Metabolic Typing” for more information about Metabolic Typing and diet.

Dangers of Protein

While the concerns over high protein intake have been blown somewhat out of proportion over the years, there are a few precautions that need to be taken.

  • Individuals with kidney problems will most definitely need to moderate their protein intake as by-products of protein degradation are filtered through the kidneys.
  • Kidney stones seem to be increasing at alarming rates. Some health experts believe that as more people follow high-protein diets, this trend is likely to continue. However, recent research shows that a beer gut is just as important as a risk factor.
  • Perhaps the most worrisome issue surrounding protein intake is the diminishing quality of protein from animals. Factory farms, environmental pollution and medication use has seriously cast doubt over the safety of regularly consuming animal proteins. In addition, high protein diets are a serious stressor for Mother Nature. Factory farming is one of the true horrors of modern society. It is strongly recommended that protein rich foods such as chicken and beef come from natural sources and from farmers who do not pump their animals full of hormones and antibiotics. In addition, animals that graze on open pasture have a better nutrient profile.

When to Consume Protein

Consuming protein prior to exercise (especially resistance exercise) appears to result in an improved net protein balance, which can bring about greater gains in muscle mass and strength than with just training alone. The amount of protein needed for this effect appears to be small – maybe no more than the amount in an egg.

For a long time, it was assumed that only the consumption of carbohydrates during exercise would bring about improved exercise performance. However, recent research is showing more promise for the combination of carbohydrate and protein as a way to improve time to exhaustion. The reasons for this benefit are still in question, but increased insulin concentration and thus uptake of nutrients is believed to be one mechanism.

There has been some indication that consuming protein immediately following exercise is crucial for recovery and gains from training. The research is getting closer to proving that this practice is indeed very important. However, there is some indication that calories either from carbohydrates, proteins or a combination of both is just as if not more important for exercise recovery. What needs to be proven is whether protein consumption 30 minutes after a workout would be significantly better than protein intake an hour or more after a workout and exactly how much protein is needed with respect to long-term lean body mass growth and strength. Physiologically, it makes sense that consuming protein as close to a workout as possible would bring about better results, but the hard data still needs to be fine-tuned. Despite this, it is still prudent to recommend the consumption of high quality proteins such as whey, chicken and eggs soon after an exercise session to promote training results and reduce muscle soreness, especially if it involved resistance training.

Data indicates that proteins that provide the largest amount of essential amino acids are better for promoting anabolism. In particular, the branch chain amino acid leucine seems to work synergistically with insulin to stimulate protein synthesis. Carbohydrate consumption alone following exercise has also shown to produce a more favorable anabolic environment.

It is interesting to note that the addition of protein to a carbohydrate solution following exercise has shown to increase glycogen (carbohydrate stores) recovery after exercise more than just carbohydrates (except when large amounts of carbohydrate are consumed for several hours). It is assumed that higher insulin levels are responsible for this outcome.

References:

  1. Burke, D.G. et al. The effect of whey protein supplementation with and without creatine monohydrate combined with resistance training on lean tissue mass and muscle strength. Int J Sport Nutr Exerc Metab. 2001 Sep;11(3):349-64.
  2. Flakoll, P.J. et al. Postexercise protein supplementation improves health and muscle soreness during basic military training in Marine recruits. J Appl Physiol. 2004 Mar;96(3):951-6. Epub 2003 Dec 02.
  3. Ivy, J.L. et al. Effect of a carbohydrate-protein supplement on endurance performance during exercise of varying intensity. Int J Sport Nutr Exerc Metab. 2003 Sep;13(3):382-95.
  4. Jentjens, R. & Jeukendrup, A. Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Med. 2003;33(2):117-44.
  5. Layman, D.K. The role of leucine in weight loss diets and glucose homeostasis. J Nutr. 2003 Jan;133(1):261S-267S.
  6. Layman DK. Role of leucine in protein metabolism during exercise and recovery. Can J Appl Physiol. 2002 Dec;27(6):646-63.
  7. Lemon, P.W. et al. The role of protein and amino acid supplements in the athlete's diet: does type or timing of ingestion matter? Curr Sports Med Rep. 2002 Aug;1(4):214-21.
  8. Lemon, P.W. et al. Beyond the zone: protein needs of active individuals. J Am Coll Nutr. 2000 Oct;19(5 Suppl):513S-521S.
  9. Rankin, J.W. et al. Effect of post-exercise supplement consumption on adaptations to resistance training. J Am Coll Nutr. 2004 Aug;23(4):322-30.
  10. Roy, B.D. et al. The influence of post-exercise macronutrient intake on energy balance and protein metabolism in active females participating in endurance training. Int J Sport Nutr Exerc Metab. 2002 Jun;12(2):172-88.
  11. Thyfault, J.P. et al. Effects of liquid carbohydrate ingestion on markers of anabolism following high-intensity resistance exercise. J Strength Cond Res. 2004 Feb;18(1):174-9.