Protein For Natural Bodybuilding? Everything You Need to Know.

It goes without saying that hitting your daily protein is an essential part of being a competitive bodybuilder. Failing too, limits your ability to maximise muscle growth, recover adequately from intense training and retain the lean tissue you’ve trained so hard to build.

Whether you’re deep in contest prep or building your physique in the off-season, protein is the foundation of your diet. But how much do you actually need? Is there merit to consuming above the often-cited 2.2 g/kg? Does timing really matter? And what about the ideal foods/sources?

This article unpacks the latest scientific research on protein intake for natural athletes & covers topics such as daily requirements, timing strategies, meal distribution and food quality. Whether you’re a coach, this guide will give you practical, evidence-based recommendations to improve your result.

Why Protein Matters in Bodybuilding

Protein provides the amino acids your body needs to build and repair muscle tissue. Every time you lift, you create small amounts of damage to your muscle fibres and protein helps rebuild them to be stronger and thicker than before. This process, called muscle protein synthesis (MPS), is what defines hypertrophy.

As a natural bodybuilders, ensuring you’re consuming an adequate amount of daily protein is crucial to maximise your hypertrophic potential. Moreover, for those dieting in a caloric deficit, the chances of lean tissue retention is bolstered when consuming sufficient protein, with your daily requirements needing to be higher than that of a building phase.

How Much Protein Should You Eat Each Day?

The RDA Isn’t Enough for Athletes

Let’s start with the basics. The current Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight (g/kg BW). But this is designed for sedentary adults it’s consideration is to simply prevent deficiency. Thus, it’s nowhere near enough for bodybuilders looking to maximise their progress in the gym.

The “Sweet Spot”: Recommended Range

If your goal is to build muscle and recover efficiently, research consistently supports a daily protein intake of 1.6 to 2.2 g/kg BW (Morton et al., 2018; Jäger et al., 2017). This range covers most of the population and aligns with guidelines from the International Society of Sports Nutrition (ISSN).

Why this range?

At around 1.6 g/kg, muscle protein synthesis is maximised for most people
Going up to 2.2 g/kg accounts for individual variability, training volume, and lean body mass

Going below 1.6 g/kg risks insufficient recovery, muscle loss, and underperformance, particularly for those in the diet condition.

Protein Requirements During Contest Prep

When calories go down, protein needs go up. Contest prep represents a intensively long duration of increased energy expenditure (hard training & daily step/cardio output) coupled with reduced energy availability (dieting/calorie deficit). Therefore without sufficient protein, your body will tap into muscle stores to better meet its energetic needs.

A landmark review by Helms et al. (2014) suggests 2.3 to 3.1 g/kg of lean body mass (LBM) is ideal for preserving muscle in lean, resistance-trained athletes. Translated to body weight, this equates to roughly 2.0-2.7 g/kg BW for most competitors.

Why more?

Caloric deficits increase muscle protein breakdown
Training stress stays high (or even increases during prep)
Hormonal shifts (like reduced testosterone and IGF-1) make muscle retention harder
Higher protein helps blunt appetite and may preserve metabolic rate (to a degree)

Is More Protein Always Better?

You’ve likely heard of bodybuilders eating 3 or even 4 grams of protein per kilogram of body weight. But does this provide extra gains?

Muscle Gains Plateau Beyond ~2.2 g/kg

Several well-controlled studies have shown that going above 2.2 g/kg doesn’t lead to greater muscle gain, assuming energy needs are met (Morton et al., 2018; Antonio et al., 2014, 2016).

A meta-analysis of over 49 studies found no additional fat-free mass gains beyond 1.6-2.2 g/kg/day.
In high-protein trials (up to 4.4 g/kg/day), researchers found no additional lean mass accrual, but also no harm (Antonio et al., 2014).

The Benefits of Very High Protein Diets (3.0-4.0 g/kg)

While extra protein may not build more muscle, it may be particularly useful for those in fat loss phases.

Greater satiety: Protein keeps you full, which helps reduce overall food intake
Higher thermic effect: Digesting protein burns more calories (TEF = ~20–30%)
Body recomposition: In some studies, participants on higher protein diets lost more fat and retained more muscle during a cut, despite total calories being the same (Longland et al., 2016).

So, very high protein intakes may offer advantages for fat loss and adherence, but don’t expect more muscle mass just from increasing protein alone.

Timing Matters: When You Eat Protein Counts

While your total protein intake is the biggest factor, when you eat your protein also plays a role in muscle growth, recovery, and tissue retention. For natural bodybuilders, especially during contest prep, timing is an important consideration to help maximise protein & avoid muscle loss during long gaps without food.

Let’s look at three key areas:

1. Protein Around Your Workout (Pre & Post)

The idea of the “anabolic window” has evolved. You don’t need to chug a protein shake within 30 seconds of your final rep, but you do want to ensure your muscles have access to amino acids before and after training.

The ISSN recommends eating a protein-rich meal 1-2 hours before training, and consuming another 20-40 grams of protein within 2 hours after your session (Jäger et al., 2017).

If you train fasted, post-workout protein becomes even more urgent. But if you ate a balanced meal 60–90 minutes beforehand, you can relax as your muscles are already in a fed state.

A practical tip would be to consume a pre-training meal consisting of 0.3-0.5 g/kg of protein with some carbs. Following your training, consume another protein-rich feeding & you’re likely ticking this box.

2. Meal Frequency: 3-6 Protein Feedings Per Day

Watch some of the greatest late 1900s to early 2000s bodybuilders & you’ll see them regularly preach the need for 6 to 8 meals per day. This old school model for meal frequency isn’t necessary, but spreading your protein out does matter. Let’s explore why.

Muscle protein synthesis (MPS) rises after a protein-rich meal, then returns to baseline in about 3-5 hours. So if you only eat twice a day, you’re missing multiple opportunities to stimulate growth.

Areta et al. (2013) found that four evenly spaced protein feedings triggered more MPS than two large meals or eight mini ones.
The ISSN recommends eating protein every 3-4 hours, aiming for at least 3, ideally 4-6 meals per day.

3. Pre-Sleep Protein: Fuelling the Overnight Fast

Sleep is when most of the magic (recovery) happens, and your muscles still need fuel during that time. Enter: pre-sleep casein.

Casein is a slow-digesting protein that provides a steady stream of amino acids overnight. Studies show that 30–40 g of casein before bed can improve overnight MPS and support muscle maintenance, especially during caloric restriction (Snijders et al., 2015).

Examples of slow digesting proteins for the overnight fast include casein protein powder, low-fat cottage cheese, greek yoghurt with whey mixed in or a blend of slower digesting plant proteins for plant-based athletes.

Per Meal Dosing: The “Leucine Threshold”

You’ve probably heard that your body can only absorb 30 grams of protein per meal but this has been severely debunked. Your body absorbs nearly everything you eat. The question should be, “how much of it is partitioned to building muscle?”

This is where the leucine threshold comes in.

Leucine is an essential amino acid that acts as a trigger for MPS. To maximise MPS, your meal needs to contain ~2.5-3.0 grams of leucine which typically means about 0.4-0.5 g of protein per kilogram of body weight per meal (Moore et al., 2009; Aragon & Schoenfeld, 2013).

As an example, a 75kg athlete would then need to consume between 30-40g of high quality protein per meal to maximise muscle growth. Consuming less than this may weaken the MPS response & eating more than this may not result in a larger spike. The excess may simply go to other bodily functions or be used as energy.

Protein Quality: Not All Sources Are Equal

Protein quality refers to amino acid profile, digestibility, and bioavailability. Animal proteins are typically higher in essential amino acids (EAAs), especially leucine, and are more easily digested when compared to plant-based protein.

Animal-Based Protein (Complete, High Leucine)

Whey (11% leucine) – fast digesting, ideal post-workout
Casein – slow digesting, ideal before bed
Eggs, poultry, beef, fish – complete proteins, high bioavailability

These sources are high in leucine, easy to portion, and convenient for contest prep when calorie control is critical.

Plant-Based Protein (Varying Quality)

Soy and pea protein – high-quality, ~8% leucine, nearly complete
Rice, lentils, quinoa – lower in one or more EAAs
Blended plant protein powders – designed to match animal proteins

For vegans or plant-based athletes, it’s absolutely possible to build and retain muscle, but total protein needs may be slightly higher (e.g. 2.0–2.4 g/kg BW) to account for digestibility and amino acid gaps (Kim et al., 2021).

Considering plant-based proteins contain less diversity in their amino acid protein, a practical tip would be to combine protein sources in order to create a more complete amino acid profile. E.g. combine rice + beans or lentils + quinoa within a meal, or supplement with soy or pea-based protein powder on the side.

Conclusion: The Protein Framework

If you’re a natural bodybuilder, protein is your insurance policy. It supports growth, protects lean mass, and enhances recovery. But more isn’t always better. Instead, strategic intake based on training phase, timing, distribution, and source delivers the greatest return on investment.

Here’s a quick recap:

1.6–2.2 g/kg BW is ideal for hypertrophy in the off-season
2.3–3.1 g/kg LBM is optimal during contest prep
Split protein into 4–6 meals with 0.4–0.55 g/kg per meal
Prioritise complete, high-leucine sources or combine plant proteins to fill any gaps the amino acid profile
Use peri-workout and pre-bed protein feedings to optimise recovery and retention

Coaches: Use these numbers as a starting point, but remember to adjust based on biofeedback, recovery, and long-term adherence.

Athletes: Consistency is King. Strike your protein intake day after day, and your physique will reflect it.

References

Antonio, J., Ellerbroek, A., Silver, T., Vargas, L., & Peacock, C. (2016). A high protein diet has no harmful effects: A one-year crossover study in resistance-trained males. Journal of Nutrition and Metabolism, 2016, 9104792. https://doi.org/10.1155/2016/9104792

Antonio, J., Peacock, C., Ellerbroek, A., Fromhoff, B., & Silver, T. (2014). The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. Journal of the International Society of Sports Nutrition, 11(1), 19. https://doi.org/10.1186/1550-2783-11-19

Areta, J. L., Burke, L. M., Ross, M. L., et al. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. The Journal of Physiology, 591(9), 2319-2331. https://doi.org/10.1113/jphysiol.2012.244897

Hevia-Larrain, V., Gualano, B., Longobardi, I., et al. (2021). A plant-based high-protein diet in combination with resistance training improves body composition in healthy adults: A randomized controlled trial. Sports Medicine, 51(5), 989-1002. https://doi.org/10.1007/s40279-020-01364-0

Helms, E. R., Aragon, A. A., & Fitschen, P. J. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: Nutrition and supplementation. Journal of the International Society of Sports Nutrition, 11(1), 20. https://doi.org/10.1186/1550-2783-11-20

Jäger, R., Kerksick, C. M., Campbell, B. I., et al. (2017). International Society of Sports Nutrition Position Stand: Protein and exercise. Journal of the International Society of Sports Nutrition, 14(1), 20. https://doi.org/10.1186/s12970-017-0177-8

Kim, I. Y., Schutzler, S., Schrader, A., Spencer, H. J., Azhar, G., & Wolfe, R. R. (2021). Quantity of dietary protein intake, but not animal or plant protein origin, is associated with muscle mass and strength in healthy older adults: A systematic review and meta-analysis. Nutrients, 13(2), 391. https://doi.org/10.3390/nu13020391

Longland, T. M., Oikawa, S. Y., Mitchell, C. J., Devries, M. C., & Phillips, S. M. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: A randomized trial. The American Journal of Clinical Nutrition, 103(3), 738-746. https://doi.org/10.3945/ajcn.115.119339

Moore, D. R., Robinson, M. J., Fry, J. L., et al. (2009). Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. The American Journal of Clinical Nutrition, 89(1), 161-168. https://doi.org/10.3945/ajcn.2008.26401

Morgan, P. T., et al. (2021). The effect of protein source on muscle mass and strength: A systematic review and meta-analysis. Nutrition Reviews, 79(3), 370-388. https://doi.org/10.1093/nutrit/nuaa022

Morton, R. W., Murphy, K. T., McKellar, S. R., et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training–induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384. https://doi.org/10.1136/bjsports-2017-097608

Schoenfeld, B. J., Aragon, A. A., & Krieger, J. W. (2013). The effect of protein timing on muscle strength and hypertrophy: A meta-analysis. Journal of the International Society of Sports Nutrition, 10(1), 53. https://doi.org/10.1186/1550-2783-10-53

Snijders, T., Res, P. T., Smeets, J. S., et al. (2015). Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men. Journal of Nutrition, 145(6), 1178-1184. https://doi.org/10.3945/jn.114.208371