How much protein do you really need?
— By Casey Jones
The complexities of macronutrient intake stumble athletes and coaches alike. How much protein should be eaten before and after a workout? Can we only absorb a certain amount of protein in one sitting? Does it really matter at the end of the day? There are myths that the fitness industry maintains with respect to dietary intake, and we’ll try and debunk a few of these in this article.
What is protein?
Protein is present in every cell of the human body. They carry out a vast array of functions including the metabolism of food, DNA synthesis, and transport of molecules.
When we take in protein, the body breaks it down into its constituent amino acids that then go on to make new proteins that our body can use. There are 20 amino acids, and each source of protein has a different amino acid profile. Some amino acids are essential, meaning that our body cannot produce them on its own, and therefore must be taken in by dietary means.
Animal proteins like meat, fish, dairy products and eggs are complete protein sources, meaning they contain all of the essential amino acids. Quinoa and soybeans are also complete proteins. If you are vegan or vegetarian, it’s important to have a variety of protein-rich foods throughout the day since most plant-based proteins are incomplete proteins.
Q: How much protein should I eat each day?
A: The International Society of Sports Nutrition (ISSN) states that protein intake of 0.6-0.9 grams per pound of bodyweight for those that are physically active is both safe and may improve adaptation to training (1). You may have heard that higher levels of protein may be beneficial for muscle gain, but this may not be the case.
For a 160 pound person, this would involve an intake of 144 grams of protein per day. The ISSN also states that protein supplements are suitable to reach this level of intake.
Q: Do I waste extra protein that my body doesn’t absorb?
A: Not necessarily! The “magic number” of 30 grams of protein per sitting is a popular target in some fitness circles. However there is no research to say that this amount of protein is optimal for absorption. A 2000 study in young women even showed that spreading out protein intake throughout the day versus all at once did not affect how much protein they retained (4). The folks at Examine.com cover this topic in great detail (5).
Q: Does my protein intake timing matter?
A: Sort of. Research shows that protein doses at 0.4-0.5 g/kg of lean body mass, both before and after exercise may maximize the muscle-building response from strength training (6). Although a debate exists if there is a muscle building “window of opportunity” following exercise, 20-40 grams of a protein supplement before and after exercise is a safe bet. The authors of a 2013 review suggest that these pre- and post-exercise meals should not be separated by more than 3-4 hours (6). Depending on your individual ability to digest food before a workout, having some protein anywhere from 1-2 hours before training is a good plan.
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Q: What about protein and weight loss? Should I eat more?
A: Diet isn’t a one-size-fits-all approach. Your dietary protein intake should depend on your goals, activity levels, and body type. If your goals involve weight loss, increasing your protein intake may make you feel more full and cause you to eat less. Protein and fat are more slowly digested than carbohydrates, so may make you feel more full.
Increasing your protein intake has several benefits: improvement of muscle building after a workout, feeling more full, and improvement of recovery and immune function. Follow the guidelines laid out above and you’ll be on your way to improving your diet.
Casey Jones is a master's in science student at Dalhousie University, where he studies the link between the human microbiome and pediatric Crohn’s disease in Nova Scotians.
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