If weight training is important for building muscle, so is consuming the right amount of protein. The amount of protein needed to optimize muscle growth has been the subject of ongoing research and controversy. In this article, we discuss current research evaluating the role of protein in muscle growth and how much a person should consume each day.

Proteins are present in all cells and tissues of the body. Although it has many vital roles in the body, protein is essential for muscle growth as it helps repair and maintain muscle tissue. The current recommended intake of nutrients to prevent deficiencies in low-activity adults is 0.8 grams (g) of protein per kilograms (kg) of body weight. However, recent research suggests that people trying to build muscle need more than that.

Consuming less protein than the body needs has been linked to reduced muscle mass. In contrast, protein intake above daily amounts can help increase strength and lean body mass when combined with resistance training.

Why is protein important for building muscle?

Proteins are made up of amino acids, which serve as building blocks in cells and tissues in the body. There are 20 amino acids that combine to form proteins. While some can be synthesized by the human body, others cannot. The nine amino acids that the body cannot make are called essential amino acids. They must be obtained through food.

When a person eats protein, it is digested and broken down into amino acids, which are involved in many processes in the body, including tissue growth and repair, immune function and energy production. Like other tissues in the body, muscle proteins are constantly being broken down and rebuilt. To build muscle, a person must consume more protein than is broken down. This is often referred to as a net positive nitrogen balance because proteins have a high nitrogen content.

If a person does not consume adequate amounts of protein, their body tends to break down muscle to provide the body with the amino acids needed to support body functions and preserve more important tissues. Over time, this can lead to a decrease in muscle mass and strength. Finally, the body uses amino acids for muscle protein synthesis, the primary driver of muscle repair, recovery and growth after intense exercise.

How much protein do you need?

Most healthy adults over the age of 19 should get between 10 and 35 percent of their daily calories from protein. One gram of protein provides 4 calories. This means that a person eating 2,000 calories per day should consume between 50 and 175 grams of protein per day.

The figure of 0.8 g per kg body weight for protein is based on the amount needed to maintain nitrogen balance and prevent muscle loss. However, it may not be appropriate to extend these recommendations to active people who want to build muscle. When it comes to building muscle mass, the ideal amount of protein a person should consume daily varies depending on several factors, including age, gender, activity level, health and lifestyle.other variables. But several studies have given us a good idea of ​​how to calculate the amount of protein that adults need to gain muscle, based on body weight.

What do the studies say?

While most studies agree that higher protein intake is associated with improved lean body mass and strength when combined with strength training, the optimal amount of protein needed to build muscle remains controversial.

Here’s what the latest research says.

A 2020 meta-analysis published in the journal Nutrition Reviews found that protein intake of between 0.5 and 3.5 g per kg of body weight can promote increased lean body mass. In particular, the researchers noted that gradually increasing protein intake, even by as little as 0.1 grams per kg body weight per day, can help maintain or increase muscle mass.

The increase in lean body mass as a result of higher protein intake declined rapidly after exceeding 1.3 g per kg body weight. Strength training suppressed this decline. This suggests that increased protein intake combined with strength training is the best solution for gaining lean mass.

Another 2022 meta-analysis published in the journal Sports Medicine concluded that higher protein intakes, in the range of 1.5 g per kg body weight per day, associated with strength training, are necessary to achieve an optimal effect on muscle strength. The researchers noted that the benefits of increased protein intake on strength and muscle mass appear to level off between 1.5 and 1.6 g per kg body weight per day.

Finally, a systematic review and meta-analysis published in 2022 in the Journal of Cachexia, Sarcopenia, and Muscle concluded that a protein intake of 1.6 g per kg body weight per day or more leads to a small increase in lean body mass in youth. resistance trained individuals. The results in older individuals were marginal.

Notably, 80% of the studies examined in this review reported that participants consumed a minimum of 1.2 g of protein per day. kg body weight per day, which is still higher than the current RDA. This may be a potential factor contributing to the diminished effects of protein intervention in combination with strength training in older adults. Although it is difficult to give exact numbers due to varying study results, the optimal amount of protein for muscle building appears to be between 1.2 and 1.6 g per serving. kg body weight.
This means that a man of 81.8 kg, for example, should consume between 98 and 131 g of protein per day, in combination with strength training, to promote muscle growth.

What are the best sources of protein?

A person can meet their daily protein needs by consuming animal and vegetable protein sources.

Sources of animal protein include

lean meat (beef, pork or lamb)
Poultry
egg
fish and shellfish
dairy products
whey protein powder.

Plant-based sources of protein include

prayers
the peas
nuts
lenses
frog
soy products
protein powder of vegetable origin.

Some nutritionists consider animal protein sources to be superior to plant protein sources when it comes to building muscle mass. In fact, they are complete proteins that contain all the essential amino acids that the body needs in sufficient quantity. They are also easy to digest. Some experts consider most plant proteins to be incomplete proteins because they do not contain all the essential amino acids. However, individuals can combine incomplete protein sources to form a complete protein. For example, rice and beans, hummus and pita bread or peanut butter on wholemeal bread.

How much protein is too much?

Doctors generally agree that healthy adults can safely tolerate long-term protein intake of up to 2g per day. kg body weight per day without side effects. However, certain groups of people, such as healthy, well-trained athletes, can tolerate up to 3.5 g per kg body weight. Most studies suggest that consuming more than 2 g of protein per kg body weight per day can lead to long-term health problems.

Symptoms of excessive protein intake include:

discomfort in the intestine
nausea
dehydration
fatigue
weight gain
irritation
headache.

The more serious risks associated with chronic overconsumption of protein include:

heart disease
epileptic seizures
kidney and liver damage

Finally

When combined with resistance training, protein intake above current RDAs can promote muscle building. The best way to meet your daily protein needs is to eat lean meat, fish, beans, nuts and legumes. Since the optimal amount of protein a person needs depends on their age, health status, and activity level, you should consider consulting a health care professional or dietitian to determine how much protein you need.

* Presse Santé strives to convey health knowledge in a language that is accessible to everyone. IN NO CASE can the information given replace advice from a healthcare professional.