The two most important nutritional considerations for men and women who are trying to gain muscle mass are total energy intake and sufficient dietary protein consumption. The ability to promote muscle building response ─ termed in the scientific literature as muscle protein synthesis ─ is an energetically expensive process. Therefore, as a first consideration to maximise gains in muscle mass, energy intake must exceed energy expended. The second key consideration is dietary protein intake. The importance of dietary protein for muscle building stems from the need to supply amino acids, i.e. the building blocks of muscle protein, to the working muscles following exercise in order to accumulate more muscle protein mass. Over the past 20 years, scientific literature has advanced our understanding of the recommended amount, type and timing of protein intake in order to maximise muscle mass gain.
Optimising amount of protein intake
Current guidelines for target daily protein intake for athletes striving to gain muscle mass range from 1.2-1.8 grams per kilogram body mass per day. However, recent modifications in guidelines regarding how much protein should be consumed have moved towards a more refined approach by expressing recommendations on a meal-by-meal, rather than on a total daily, basis. Within a controlled laboratory setting using sophisticated methodology, we and others have measured the muscle building response after trained volunteers (18-35 years old) consumed a drink containing either 0, 5, 10, 20 or 40 grams of whey or egg protein immediately after an intense leg-only resistance-exercise workout [1,2]. In both studies, the average body mass of participants was 85 kg and both studies showed that the muscle building response was maximised by the 20 gram dose of protein. The additional 20 grams of protein contained in the 40 gram did not additionally contribute to the muscle building response. We have therefore established that on a meal-by-meal basis, 20-25 grams (equal to ~0,30 grams per kilogram body mass) of high-quality protein (see below) is sufficient to promote maximal muscle building response after leg-only exercise. In practice, 1 scoop of ISO100 Hydrolyzed protein powder, or ~700 mL of skimmed milk, or 4-5 eggs, or 100 g of lean beef are examples of foods containing ~25 g of protein.
Last year we carried out a study investigating the influence of muscle mass on the optimal protein dose needed in order to maximise muscle building response to a workout . We recruited 2 groups of volunteers, one with a lower amount of muscle mass (65 kg) and one with a relatively larger amount of muscle mass (70 kg). We assessed the muscle building response to different amounts of protein (either 20 or 40 grams) after a whole body weight-lifting routine, rather than limiting the exercise workout to a leg-only routine as was the case in the previous studies [1,2]. We showed that 40 grams of protein consumed post workout was more effective at stimulating the muscle building response than 20 grams of protein. This effect occurred irrespective of how much muscle mass the study participant possessed. The most likely explanation for the difference between our recent study and the previous studies is that more muscle was activated during the exercise workout in the recent study. We believe that our data indicate that the amount of muscle worked in a single session is more important to the post exercise protein dose requirement than the absolute amount of muscle the athlete possesses. However, further research is warranted to confirm this claim.
Optimising type of protein intake
The amount of protein consumed after exercise is not the only factor that influences the muscle building response. Proteins are made of chains of amino acids. Each protein has a unique amino acid composition. High quality protein is easily digested and absorbed and constitutes a relatively high content of the branched chain amino acids (valine, isoleucine and leucine) — in particular a high content of the essential amino acid leucine. The muscle building effects of consuming protein seems to be intricately linked to the leucine content of the protein and has led to the development of the “leucine trigger hypothesis”. It follows that whey protein, which is rich in leucine composition, is often touted as a high quality protein.
Optimising timing of protein intake
Recent efforts have focused on understanding the muscle building response over an entire day after consuming multiple protein-containing meals [4,5]. These studies reveal that, despite consuming the same daily protein intake (90 grams), the aggregate muscle building response over the entire day depends on the pattern of protein consumption. For example, a protein meal pattern that distributed 90 grams of protein evenly between breakfast (30 grams), lunch (30 grams) and dinner (30 grams) stimulated a greater 24-hour muscle building response compared with a protein meal pattern that skewed a large proportion of daily protein intake (~60 grams) towards the evening meal, with suboptimal doses of protein contained in breakfast (10 grams) and lunch (16 grams) meals. Taking into account the dose-response data described above [1,2] it can be assumed that when protein is evenly spread between meals, maximal muscle building response is achieved at each meal sitting.
In general, studies have shown a similar muscle building response during exercise recovery when protein is ingested immediately before exercise compared with immediately after exercise . Therefore, skeletal muscle is, at the very least, comparatively responsive to protein ingested before or after the exercise workout.
Key points for protein intake
- Protein intake is a key consideration for muscle hypertrophy.
- How much? Optimise how much protein by considering a meal-by-meal approach rather than a daily protein intake approach.
- What type? A high quality protein source is easily digested and absorbed and is proportionally high in the essential amino acids, particularly leucine.
- When? An even distribution of protein is the recommended meal pattern for maximising muscle building response over the day.
Dr. Oliver Witard is a Senior Lecturer in Nutrition and Exercise Metabolism at The University of Stirling. Oliver’s research focus is protein nutrition for maximising muscle adaptation to exercise training. His publications focus on establishing the optimal dose, source and timing of dietary protein for maximising gains in muscle mass, function and performance
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- Witard, Oliver C., et al. "Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise." The American journal of clinical nutrition 99.1 (2014): 86-95.
- Moore, Daniel R., et al. "Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men." The American journal of clinical nutrition 89.1 (2009): 161-168.
- Macnaughton, Lindsay S., et al. "The response of muscle protein synthesis following whole‐body resistance exercise is greater following 40 g than 20 g of ingested whey protein." Physiological Reports 4.15 (2016): e12893.
- Areta, José L., et al. "Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis." The Journal of physiology 591.9 (2013): 2319-2331.
- Mamerow, Madonna M., et al. "Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults." The Journal of nutrition 144.6 (2014): 876-880.
- Tipton, Kevin D., et al. "Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise." American Journal of Physiology-Endocrinology and Metabolism 292.1 (2007): E71-E76.