Protein and Strength Training: How Much Is Enough?

Guest Article by:

Michael Fouts, Registered Dietitian and Personal Trainer

Daniel Feldman, Registered Dietitian and Personal Trainer

You’re heard that protein is important for strength training. It’s one of the three big macronutrients (unless you also count alcohol) so we need a lot of it compared to micronutrients (vitamins and minerals). Beyond supporting muscle tissue repair and maintenance, protein is also responsible for producing hormones and enzymes, storage and transport of molecules like hemoglobin, and has many other critical functions.

But when it comes to strength training, how much protein is enough? To answer this, let’s consider the following:

Frequency and intensity of strength training

Those who strength train more often or lift heavier require more protein than those who strength train less often or with lighter weights.

Resistance training experience

Those with less strength training experience have a greater capacity for building muscle. Thus, they require more protein.

Calorie balance

Those in a calorie deficit require more protein to prevent muscle loss.

Muscularity

Those with more muscle mass require more protein to maintain that muscle.

Exercise other than strength training

Those with high physical activity levels outside of strength training (competitive athletes) require more protein.

Genetics

Those with a genetic predisposition towards gaining more muscle mass require more protein.

Protein requirements also vary based on your goals. Let’s look at a few examples and what the research says:

Goal: Building Muscle

Consuming 1.6g/kg of body weight (0.7g/lb) is optimal for building muscle; more than 1.6g/kg doesn’t seem to result in further muscle growth (1, 3, 4, 5, 6).

Goal: Fat loss

Consuming 1.8–2.8 g/kg of body weight (0.8–1.3 g/lb) is optimal for fat loss (1, 2, 3, 7). Fat loss goals necessitate higher protein intakes because protein is more satiating than carbohydrates and fats. Research demonstrates that people who eat high protein diets tend to have more success losing fat, largely because the extra protein helps them feel more full (2, 3).

Additionally, high protein diets have a protein sparing effect—they help prevent your body from using its own muscle as energy. The wide range of optimal protein intakes, 1.8–2.8 g/kg, will accommodate different personal preferences.

It should be stated that eating higher amounts of protein doesn’t guarantee that you won’t lose muscle while losing fat. Strength training, however, is critical in preserving muscle while losing fat (3).

Goal: Athletic Performance

Consuming between 1.3–1.8g/kg of body weight (0.6–0.8 g/lb) is recommended for most athletes (1, 3, 5, 8). More specifically, strength athletes require 1.6g/kg (0.7g/lb) (1, 3, 5, 8), and endurance and ultra endurance athletes require slightly less protein—1.2–1.4 g/kg and 1.5–1.7 g/kg, respectively (1, 3, 8). These recommendations are for athletes seeking to maintain their weight, and account for their high activity levels.

Keep in mind that studies assessing protein needs for individuals who strength train generally assess men with body fat percentages ≤20%; comparatively few studies assess women.

If your body fat percentage is higher than 20%, the ranges above will overestimate your protein requirements. You can base protein recommendations off of lean mass, however assessing lean mass accurately is very difficult unless you have access to expensive, laboratory-grade equipment. Even more accessible forms of measuring body fat percentage are prone to a high error range, making them fairly useless for our purposes(and potentially upsetting if the error skews on the high end).

Instead, we suggest one of the following approaches:

Consume between 120 and 160 grams daily

Maximal protein synthesis has been shown to be achieved from servings of 20-25g of high quality protein, consumed 3-4 times per day (1, 3). There are diminishing returns after this, and there seems to be no effect beyond 40g per serving (1, 3). This isn’t to say eating more protein is bad or useless, as protein synthesis(building muscle) isn’t the only function of consuming protein. There is also no research that suggests any harm or risk in healthy individual of consuming even upwards of 4 grams of protein per pound of body mass. And trying to consume that much protein is so prohibitively difficult and unpleasant as to make it nearly impossible anyway.

Side note: high quality protein = animal protein with all of the essential amino acids. If you’re getting your protein from plant sources you’ll need a little bit more, likely 25-30g instead of 20-25g.

Most people have 3-4 eating opportunities per day (eg. 3 meals, 1 snack), so for most, 120g is a good minimum target and 160g is a good maximum. Further, with the exception of fat loss, this range satisfies the goal ranges above for anyone weighing less than 100kg.

Find an intake that optimal for you

We all have different eating styles and food preferences. For some people, it’s challenging to eat more than 100 grams of protein daily from food alone. Ideally food should be your primary source of protein, and supplements (e.g., protein powders) should supplement your diet. To determine what’s practical for you, increase your protein intake by consuming protein-focused meals (e.g., fill your plate with ¼ to ⅓ of a protein-dense food per meal) and snacks. Record a few days of food intake and assess how much protein you can comfortably consume. Compare your intake to the ranges listed in this post, and then determine what’s practical given your goal(s).

Take home message

Determine your protein needs based on your goal, as outlined above. If you are significantly overweight, aim for a minimum of 120g, and up to 160g. You may opt to eat more than 160 grams if you can comfortably eat more protein as part of your usual diet, or if you have a fat loss goal and the added protein helps manage your hunger.

It’s also important to highlight the law of diminishing returns — excessive protein intakes will not increase muscle mass. Consistent strength training with sufficient intensity is of far more importance for building muscle mass. And there is a limit to the speed at which increases in muscle strength and size occurs— higher protein intakes will not affect this.

Protein and Strength Training: How Much Is Enough?

References

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Protein and Strength Training: How Much Is Enough?

References

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