To say, “Protein is the most important macronutrient” is like saying, “The heart is the most important organ.”

Without the other organs, the heart is useless. Without the other macronutrients, fat and carbohydrate, protein doesn’t matter, either.

With that said, we have found that eating enough protein should be the top priority for anybody who does CrossFit or strength training.

Consider this post your protein master-class. You will learn about protein’s role in the body, how much you need to consume each day, how much is too much protein, and best protein sources from food.

What is Protein’s Role in the Body?

Protein, as a macronutrient, should be the number-one focus of anybody who includes strength training (whether with weights or bodyweight) in their exercise routine.

The roles of protein in the body are numerous, and include:

  • Tissue structure and function
  • Enzyme and hormone production
  • Energy (through gluconeogenesis)
  • Immune system function
  • And more…

Protein is the most important macronutrient to focus on consuming because our bodies are constantly breaking down and rebuilding. Exercise has an effect on this breaking down and rebuilding process, called “protein turnover” which we will now explore.

Why Protein is Important for Exercise

Exercise causes stress to our muscles, and this sends signals to suggest that our current setup just isn’t doing the job. The body will want to be adequately equipped to handle the same stress next time, so it kick-starts the upgrade process.

The upgrade involves breaking down your inadequate muscle proteins and enzymes (which assist in energy production), and then the body uses the amino acids you consume from food to rebuild.

Your body has small “pools” of amino acids that it draws from for this rebuilding process. These amino acid pools are actually more small bathtubs with the drain open.

To stay full, these amino acid pools need a constant flow of new amino acids from your diet. Exercise increases your body’s need for amino acids from dietary protein.

Without an adequate supply of essential amino acids from your diet, your body will cannibalize its muscle tissue which can lead to a slower metabolism, downregulation of anabolic hormones, compromised immune system and poor athletic performance.

How Much Protein Should You Consume?

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If you are an athlete, the short answer is that research says .82-1g of protein per pound of bodyweight.

For a 160lb athlete, this means 132-160 grams of protein per day.

You should eat closer to 1g of protein per pound of bodyweight if:

  • You are new to strength training.
  • You are on a “calorie deficit” trying to lose weight.


BodyweightProtein for BeginnersProtein for Experienced LiftersProtein if Cutting Weight
120lbs120 grams99-108 grams>108grams
140lbs140 grams115-126 grams>126 grams
160lbs160 grams132-144 grams>144 grams
180lbs180 grams148-162 grams>162 grams
200lbs200 grams164-180 grams>180 grams


An interesting finding from the sports research world is that newer strength athletes actually have higher protein requirements than trained strength athletes.

This seems counterintuitive. You would think a trained athlete with more muscle and lifting more weight would need more protein to support their muscle, but studies show that, pound for pound, the untrained athlete needs more protein.

The hypothesis is that an untrained athlete is making huge and rapid gains while the experienced athlete is fighting for inches.


How Much is Too Much Protein?

Research suggests that in both healthy populations, and athletic populations, high protein intakes do not have any adverse effects.

As long as you have healthy kidneys and no pre-existing renal disease, high protein diets have been shown repeatedly to produce good outcomes on body composition in both healthy and obese populations.

Getting Protein From Food

When it comes to food, there is actually a difference in protein quality.

Some foods have “complete” proteins, meaning they contain all of the essential amino acids that you can only get from your diet. Incomplete proteins lack one or more of the essential amino acids.

Protein quality is measured in a number of ways. These methods assess the ability of a food to deliver the essential amino acids necessary to function.

Protein Efficiency Ratio, Biological Value and Net Protein Utilization are measures of protein quality that are based on rodent models, whereas Protein Digestibility Corrected Amino Acid Score (PDCAAS) is based on human models and identifies the “limiting” amino acid in foods.

Animal proteins like meat, milk and eggs are all complete proteins. The best sources of protein from animals, as measured by their PDCAAS are:

  • Salmon
  • Whey
  • Eggs
  • Beef/Poultry

Plant proteins are often incomplete, but the body digests and assimilates 90% of the protein it digests. By combining two or more plant foods with complementary amino acids, you are still giving the body the raw materials it needs to rebuild.

Some high-quality sources of complete plant proteins are:

To feed the 160lb human from our example enough protein, it would take just under a pound of meat, a few eggs, and a scoop of protein powder.


Coming Up Next


What does the body need carbohydrate for? Do carbohydrates make you fat? Is high carb or low carb better for you?

Now that you know the role of protein in the body, click here to learn the fascinating role of carbohydrate in the body and exercise recovery.