This article discusses the optimal protein intake for muscle growth, drawing on insights from a conversation with muscle metabolism and protein researcher, Jorn Trommelen.
The roles of carbohydrates and fats in muscle protein synthesis are less direct than protein. While carbohydrates stimulate insulin release, insulin primarily inhibits muscle protein breakdown, an effect achievable with protein alone. Fats don’t have a direct impact on muscle protein synthesis, but their form (oil vs. solid) can influence protein digestion and absorption. Adequate calorie intake is essential for muscle growth, whether from carbohydrates or fats, but doesn’t need to be per meal. A consistent calorie deficit over several days can reduce muscle protein synthesis.
Carbs are often consumed post-workout in bodybuilding, but the necessary insulin levels can be achieved through protein alone. A study comparing whole eggs to egg whites found whole eggs stimulated more muscle protein synthesis, possibly due to other nutrients like cholesterol. The speed of protein digestion influences the anabolic response. Whey protein, being rapidly digestible, is more anabolic when consumed as a bolus compared to sipping it over time.
While hitting daily macro targets is important, focusing solely on this can overlook other factors contributing to muscle growth. Collagen protein, while an animal-based protein, lacks essential amino acids like leucine, making it a poor choice for muscle building compared to high-quality protein sources.
A meta-analysis recommends 1.6 grams of protein per kilogram of body weight for optimal muscle growth, with an upper limit of 2.2 grams per kilogram. This roughly translates to 0.7 to 1 gram per pound of body weight. Factors like age, training volume, and body composition can influence individual protein needs. Older adults, individuals with obesity, and those engaging in full-body training might require the higher end of this range.
Surprisingly, lean body mass doesn’t appear to heavily influence protein requirements, although more research is needed. A blanket protein recommendation might not be suitable for everyone due to individual variability.
Protein quality plays a role, with animal-based proteins generally being higher in essential amino acids compared to plant-based sources. Plant-based proteins often lack one or more essential amino acids, limiting muscle growth. Vegans can compensate by consuming more plant-based protein or combining different sources to ensure a complete amino acid profile. Leucine supplementation can also be beneficial for vegans due to its role in stimulating muscle protein synthesis.
While total daily protein is crucial, distribution also matters. Studies suggest distributing protein across multiple meals can be more beneficial than consuming it in a few large meals. A frequency of four meals per day, including a pre-sleep meal, seems optimal. Intermittent fasting, while not detrimental, might not maximize potential gains.
The “muscle full” effect, where muscle protein synthesis plateaus beyond a certain protein intake, is challenged by research showing continued response to protein after exercise.
The majority of consumed protein isn’t directly used for muscle building. A significant portion goes to other tissues, with the gut being a major consumer. The remaining protein is either oxidized or used for other bodily functions.
A pre-sleep protein intake, particularly a slow-digesting protein, can be beneficial for maintaining muscle protein synthesis overnight. Around 30-40 grams seems effective, with no adverse effects on fat gain, appetite, or sleep quality.
For maximizing muscle growth, increasing training volume progressively and ensuring adequate sleep are key, in addition to optimizing protein intake and distribution. A pre-sleep protein serving can contribute to overnight muscle recovery and growth.
