11 Dec 2023 Article

Should you consume more protein or use protein shakes when you exercise? In this article I will answer this question.

A few years ago I followed a post-graduate training as a sports dietitian. During the training I learned what I already thought: that most stories about sports and food are nothing more than myths. One of these myths is that professional athletes have to consume mega amounts of protein.

Before I started working on this article, I first read about recent developments in science around sports and food, and especially around protein intake and its effect on muscle building. Today I share my findings with you.

How much protein do we actually need?

First, let’s count how much protein we need per day.

Under normal circumstances, a healthy adult needs about 0.83 grams of protein per 1 kilogram of body weight per day. For example, if your weight is 60 kg then you need 60 × 0.83 = 50 grams of protein per day. For vegetarians and vegans, that amount is 20% and 30% higher, respectively. As a 60 kg vegetarian you need 60g of protein per day, and as a 60kg vegan you need 65g of protein. This is due to the poorer digestibility of plant proteins and because plant proteins sometimes contain fewer essential amino acids. These two factors determine the protein quality. Read more below.

Quality of protein

The quality of protein is determined by two factors, namely the digestibility and the amino acid content.

In general, animal proteins have a digestibility of 90-99%, while plant proteins have a percentage of 70-90% (the higher this percentage, the better). For example, protein from corn is poorly absorbed by your body. The digestibility of protein from soybeans, on the other hand, is just as good as that from an animal source.

All proteins are made up of amino acids. Amino acids are often compared to building blocks. Twenty different amino acids have to be ‘joined’ together so that a complete protein is created in the human body. Nine of these amino acids are essential. This means that our body cannot make them on its own, so we have to get these amino acids every day with food.

Plant proteins sometimes contain one or more essential amino acids in very small amounts. Such amino acids are then called limiting. Amino acids lysine and isoleucine are limiting in cereals, while methionine and tryptophan are limiting in legumes. But if you now eat cereals and beans together, you get a series of amino acids that are complementary to each other: together they form the complete set of proteins. For a long time, the advice was that the complementary amino acids should be consumed during one meal. Today, this thought has been abandoned. The recommendation is now to consume complementary amino acids during the same day.

That basically means that you (especially if you are a strict vegetarian) should eat as varied as possible.

Interestingly, eggs, milk and soy have the highest protein quality score, namely 1. Meat has a somewhat lower score of about 0.9.

How much protein do you need when you do (strength) sports?

In general, the protein requirement of endurance athletes is significantly less than that of strength athletes.

The following recommendation applies to strength athletes who train for at least one hour at least twice a week. If you train less often than that, you don’t need extra protein.

Strength athletes who want to focus specifically on increasing muscle mass are advised to (temporarily) take a little more protein than the general population. Depending on the athlete’s fitness and goals, the extra amount of protein can range from 1.2 to 2 grams of protein per kg of body weight per day. For a strength athlete who weighs 60 kilos, this amounts to 72 to a maximum of 120 grams of protein per day. The upper limit of protein requirements can be as high as 2.2 grams of protein per kilogram of body weight per day, but studies have shown that most muscle growth in healthy individuals peaks at around 1.6 grams. That is, there is a limit to muscle growth, and eating more (than 1.6 g/kg) of protein is not going to help.

Anabolic window?

Protein timing is a technique used by many who train to maximize their gain (in muscle mass). The Anabolic Window of Opportunity theory states that from the moment your workout ends, there is a critical length of time of somewhere between 45 minutes and 1.5 hours in which you must consume large amounts of high-quality protein to achieve maximum muscle growth.

This theory is not confirmed by recent scientific studies. They say that timing plays a much smaller role than we have long thought. There is a study that concludes that eating protein 3-6 hours BEFORE strength training promotes muscle growth. Another study observes that protein intake immediately before or after exercise showed no difference in muscle gain results. So don’t worry too much about that “Anabolic Window of Opportunity”.

The new recommendation is to spread the protein intake evenly over the main meals (breakfast, lunch, dinner). In practice, this means that you consume 20-40 g of protein (depending on your weight) per meal. This recommendation is supported by The International Society of Sports Nutrition.

What about protein shakes?

Protein shakes and other products such as protein bars are not necessary if you eat enough protein from whole foods every day. However, if you think that you are getting less protein on a specific day than is desirable, then of course you could take a shake. However, keep in mind that protein shakes are not only a source of protein but also a source of calories.

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If you want to train to build more muscle mass:

  • Eat 3-4 meals throughout the day: e.g. breakfast, lunch, dinner and eventually a snack. Consume 20-40 g of protein with each meal.
  • Are you vegan? Then you have to consume 30% more protein.
  • A protein shake is not necessary but can sometimes be useful if you are unable to get enough protein via whole foods.