Protein Intake Guidelines: Part 1 by Terrence Reilly
Most athletes understand the importance of protein and its role as key component to growing muscle. Eating enough protein isn’t quite the issue, however, when considering most Americans eat more protein than recommended by the Academy of Nutrition and Dietetics. Questions still exist as to how protein should be consumed, when, and what kind despite our protein rich diets. Here are a few tips to optimize your results from your training regimen through protein consumption.
1)The type of protein matters: There is a distinction in protein quality. High quality includes the full set of essential amino acids and not all protein sources have them. Quality can also be measured by leucine concentration and availability. Leucine is a relatively common amino acid found in many different foods containing protein. What makes this amino acid so special, however, is its ability to stimulate muscle protein synthesis (MPS) or muscle growth. Consuming between 2-3g of leucine has been shown to maximally stimulate MPS.1 This equates to roughly 25-35g of high quality protein in a meal.1 When you’re looking to add some leucine dense foods, look to dairy and meat products. Lean varieties of these foods can increase lean body mass and minimize unwanted weight gain. While plant sources of protein such as soy or quinoa have all essential amino acids in them, they also are more difficult to digest or can have other factors that might inhibit muscle growth.1 It is still possible to maximize MPS on a plant based diet but more protein might be necessary to have a similar response to training in comparison to meat and dairy products.
2) Consume protein around your workouts: Your training sessions can wreak havoc on your muscles and the damage caused by exercise can leave muscle tissue in a unique metabolic state. Working out elicits a molecular response that increases the sensitivity of muscle tissue to growth factors including leucine discussed previously. Research suggests that athletes can optimize their muscular development when consuming a protein rich meal after a stressful workout session.1 While MPS can extend up to 24hr after a workout eating a protein rich meal can maximize the bodies response to training and possibly extend the cells ability to recover.
3) Keep a positive nitrogen balance throughout the day: The body is constantly building up and breaking down structures throughout any given day. That metabolism can produce a lot of waste product in the form of nitrogen. Since nitrogen is a main component of amino acids, the nitrogen intake (protein consumption) and excretion can be measured to establish a positive or negative nitrogen balance. This is specifically important for athletes because your body uses the nitrogen balance as a measure for anabolism. When plenty of resources are available your body will favor cellular growth and vice versa. If you consume a protein rich meal only once per day the overall nitrogen balance maybe lower and your body might not recover effectively from your workouts. Research suggests alternating protein rich meals with carbohydrates and amino acids between those meals to maximally stimulate MPS and maintain a positive nitrogen state.
1. Smith-Ryan, Abbie. Antonio, Jose (2013). Sports Nutrition & Performance Enhancing Supplements. Linus Learning Publication. Ronkonkoma, NY 11779.