When you start lifting weights, you are presumably doing so to grow your muscles and increase your overall muscle mass. Increasing your muscle mass has additional benefits beyond just making you look better. It can also boost your metabolism and reduce your chance of injury.
As I am sure most people know, but I will mention it here in case you do not, when you are lifting weights consistently you also have to boost your protein intake to grow your muscles. As pointed out in a 2013 study conducted by the U.S. Army and Eastern Michigan University, “adequate consumption of dietary protein is critical for the maintenance of optimal health during normal growth and aging.”
So how much protein should weightlifting humans eat in a day, and how often should high-protein meals be consumed for optimal absorption and gains? Both questions will be examined below.
How Much Protein Can Human Bodies Process In A Day?
In 2018, researchers affiliated with CUNY Lehman College (New York) and California State University examined peer-reviewed research regarding maximum muscle protein synthesis, stating in the abstract of their published findings that “controversy exists about the maximum amount of protein that can be utilized for lean tissue-building purposes” for people involved in “regimented resistance training.”
“The purpose of this paper was twofold: 1) to objectively review the literature in an effort to determine an upper anabolic threshold for per-meal protein intake; 2) draw relevant conclusions based on the current data so as to elucidate guidelines for per-meal daily protein distribution to optimize lean tissue accretion.” the investigators stated about the goal of their research.
“Both acute and long-term studies on the topic were evaluated and their findings placed into context with respect to per-meal utilization of protein and the associated implications to distribution of protein feedings across the course of a day.” they stated about their methodology.
“Based on the current evidence, we conclude that to maximize anabolism one should consume protein at a target intake of 0.4 g/kg/meal across a minimum of four meals in order to reach a minimum of 1.6 g/kg/day. Using the upper daily intake of 2.2 g/kg/day reported in the literature spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal.” the researchers concluded.
Using a 180-pound (roughly 81.65 kilograms) person as an example, the optimal amount of daily protein intake is roughly 130-180 grams of protein a day. Anything beyond the 180-gram upper threshold just gets digested but not absorbed.
How Often Should You Consume Protein?
Now that we have a better scientific-based idea of how much protein to eat in a day, there is still the lingering question of how often we should eat protein throughout the day. For the answer to that question, we turn to a 2013 study conducted by researchers affiliated with the University of Texas and the University of Illinois.
The 2013 study pointed out that protein “is often skewed toward the evening meal, whereas breakfast is typically carbohydrate rich and low in protein.”
“By using a 7-d crossover feeding design with a 30-d washout period, we measured changes in muscle protein synthesis in response to isoenergetic and isonitrogenous diets with protein at breakfast, lunch, and dinner distributed evenly (EVEN; 31.5 ± 1.3, 29.9 ± 1.6, and 32.7 ± 1.6 g protein, respectively) or skewed (SKEW; 10.7 ± 0.8, 16.0 ± 0.5, and 63.4 ± 3.7 g protein, respectively).” the investigators stated about their research methodology.
The researchers determined that the “mixed muscle protein fractional synthesis rate was 25% higher” in the group that spread their protein intake evenly between their meals compared to the group that ate larger amounts of protein in some meals and less protein in other meals.
“The consumption of a moderate amount of protein at each meal stimulated 24-h muscle protein synthesis more effectively than skewing protein intake toward the evening meal.” the researchers stated. Spread your protein-rich meals out 2-3 hours at a time, and eat the same amount of protein in each meal. You can eat more than 4 meals in a day if you are super active, but adjust your protein levels per meal accordingly for optimal protein synthesis/absorption.
Boost Your Protein, But Keep Your Diet Balanced
Many fad diets preach the benefits of eating more protein, however, some of them seem to really downplay the importance of still eating a balanced diet. While a low-carb diet can help people lose fat in the short term, it is not a long-term solution and will come at the expense of your protein absorption. Don’t just take my word for it. Here is what Arnold Schwarzenegger states in his book, Encyclopedia of Modern Bodybuilding.
“Pure protein supplements that are not consumed with a meal or added carbohydrate are not metabolized efficiently. Research indicates that for protein to be utilized more for protein synthesis than for energy production, it must be consumed with additional calories, especially those from carbohydrates.” Arnold writes (pages 709-710).
“This may be no big deal if you are on a low-carbohydrate diet and expect a greater portion of your dietary protein to be used for energy, but if your goal is to get the most bang for your protein buck, make sure you include carbohydrate with your protein…” Arnold also writes.
Arnold, and many other elite bodybuilders and nutritionists, recommend that you get 40% of your calories from protein, 40% of your calories from carbohydrates, and 20% of your calories from ‘good fats’ like those found in nuts, avocados, and fish (page 727 of the Encyclopedia of Modern Bodybuilding).
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