It’s not a major source of energy except during times of starvation or long-duration exercise, but you need protein nevertheless. In fact, many components in your body from enzymes that run cellular reactions to body parts, like bones, muscles, skin, and organs are made of protein. With regard to exercise and weight training, you need protein to repair and rebuild muscle tissue. Exercise that places stress on your body also damages muscle fibers and compromises the integrity of muscle tissue. These fibers experience microtrauma and need the amino acids from protein to restore their structure. Your body also uses protein to make antibodies, enzymes, transport protein, antibodies, proteins that help regulate body fluids, and more.
What is Protein?
Protein is composed of long strands of amino acids held together by peptide bonds. All tissues throughout your body contain proteins that serve a structural role. However, proteins play functional roles too. Even the hemoglobin in red blood cells that carries oxygen throughout your body is a protein, made up of long chains of amino acids, as all proteins are. Some amino acids that makeup protein are non-essential, meaning your body can make them in adequate amounts and you don’t need to get them from diet. Therefore, even if you don’t consume these amino acids, it won’t affect muscle protein synthesis since your body can produce its own supply.
Other amino acids are essential so that you must get them from dietary sources. All total, there are 20 amino acids your body makes use of. Five of these are non-essential, nine are essential, and six are conditionally essential, meaning your body can make enough of them under most circumstances. In certain situations, as during starvation or illness, you may need to get some of these amino acids from dietary sources.
How Much Protein Do You Need Each Day?
According to the World Health Organization, an inactive adult should get 0.80 grams of protein per kilogram of body weight. They base this recommendation on data showing that getting this quantity of protein keeps your body from going into negative nitrogen balance, a situation where protein breakdown exceeds protein synthesis. Being in a negative nitrogen balance would be counterproductive if you’re trying to build muscle or hang on to the muscle you have.
Protein requirements vary from individual to individual based on lifestyle. If you work out, you need more protein than a sedentary person. Although people who work out, endurance and strength training, need more protein than that of an inactive individual who sits in an office most of the day, the ideal amount of protein is unclear and may vary with the individual. For example, it depends on how hard, and often you work out. As a general rule, double your daily protein intake if you do intense or long-duration workouts. You need the additional protein for muscle repair.
How Much Protein at Each Meal?
Here’s another question: How much protein should you get at each meal? Dietitians recommend dividing the day’s protein intake up so you aren’t getting it all at one meal. This ensures your muscles get an adequate supply of protein available. Plus, if you eat protein with each meal, it helps with satiety since protein is the most satiating macronutrient. Also, some studies show that diets high in protein modestly boost resting metabolic rate and may help with weight control. However, the effect is modest.
How much protein should you consume with each meal? Some studies suggest that consuming over 20 to 30 grams of protein per meal tops out muscle protein synthesis and taking in more has no added benefit. In one study, 30 grams of protein was effective for ramping up protein synthesis by as much as 50%, however, tripling that amount didn’t lead to a further boost in muscle protein synthesis. Other research suggests that 20 grams of protein is the ceiling beyond which muscle protein synthesis doesn’t increase more.
Does age matter? You might wonder whether the elderly need more protein to get the same anabolic response as a younger person. A study published in the Journal of the American Dietetic Association found that 30 grams of protein with a meal was enough to maximize muscle protein synthesis in older people. Therefore, there seems to be little benefit to consuming more than this quantity of protein with a meal. However, people over the age of 65 may benefit from more protein. It’s an area of ongoing research.
Based on these findings, taking in 30 grams of protein per meal is enough to maximize muscle protein synthesis without “wasting” it. What you don’t absorb ends up in the toilet. Plus, adding more protein-rich foods to a meal means you’re eating less of something else, usually fruits and vegetables. You need room on your plate for healthy fat and fiber-rich carbohydrates too. For after-workout snacks, you don’t need as much. In fact, about half that amount, 15 grams of protein would be appropriate combined with around 45 grams of carbohydrates.
Vary Your Protein Sources
One mistake people make with protein is to assume that only animal-based foods are an excellent source. Many plant-based foods, including nuts, whole grains, legumes, and even some green vegetables, contain substantial protein Plus, they are rich in fiber to help support a healthy gut microbiome. If your gut microbiome is unhealthy, it can reduce nutrient absorption from the foods you eat. Studies also suggest that eating a diverse diet is best for your microbiome. So, branching out into more plant-based sources of protein is a smart move for your health.
Take-Home Points:
- An inactive person needs around 0.8 grams of protein per kilogram of body weight. If you work out, you may need up to double that amount.
- Getting 30 grams of protein with each meal maximizes muscle protein synthesis. There’s no evidence that getting more will lead to more robust muscle protein synthesis.
- Vary your protein sources and include some plant-based protein in your diet. You’ll get the added benefit of fiber.
References:
- Physiol Behav. 2008 May 23;94(2):300-7. doi: 10.1016/j.physbeh.2008.01.003. Epub 2008 Jan 12.
- Clin Nutr. 2013 Apr; 32(2): 309–313.Published online 2012 Dec 1. doi: 10.1016/j.clnu.2012.11.018.
- J Am Diet Assoc. 2009 Sep;109(9):1582-6. doi: 10.1016/j.jada.2009.06.369.
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