Optimising growth, maintenance and preservation of skeletal muscle mass over an athlete’s career is key to success. Athletes seeking to gain muscle mass and strength during training are advised to consume high protein intakes, usually in excess of 2.0 g/kg/day. The main belief behind the large quantities of dietary protein consumption is that more protein = more muscle. However, this is not always the case. Simply meeting a daily target of protein does not always guarantee muscle growth.
In a recent study, we showed that increasing dietary protein intake from 1.7 to 2.0 g/kg/day, during a period of intensified training, did not enhance muscle protein synthesis (i.e. a key regulator of muscle growth). In this study, the extra portion of protein was provided via a high-quality whey protein supplement. And, on first glance, some may be eager to suggest that these findings support a ‘food-first’ approach, with supplements having no role whatsoever. However, I would argue that even if the extra portion of protein was from food – for example a 100 g of steak – we still would not have seen any increase in muscle protein synthesis. The reason we saw no further increase, in response to more protein, was not due to the supplement not being effective – we have shown that not to be the case here. Rather, it was due to the 1.7 g/kg of dietary protein being (i) evenly distributed (3-5 h intervals throughout the day), (ii) optimally dosed (> 0.3 g/kg per meal) and (iii) of high-quality (i.e. high bioavailability of essential amino acids, particularly leucine). Put simply, focusing on the dose, timing and quality of the protein is much more important than the total daily intake, or whether the protein comes in food or supplement form.
So, if we can maximise muscle protein synthesis without the need for protein supplementation, do protein supplements have any place in an athlete’s diet? Apparently not. However, it must be noted that the diet in this study was designed by a qualified dietician and personalised to each athlete. The food was prepared by a resident chef, portioned into ready-eat-meals, then delivered to their front doorstep every-morning, with a reminder of how to cook and when to eat the meals. The athletes were also monitored daily, having to complete checklists/questionnaires every-day to ensure they were following the diet correctly. Whilst this allowed us remarkable control during the study, it cost about €50/day per athlete. So, for athletes who do not have a qualified dietician and personal chef to hand, especially those with dietary restrictions (e.g. dieting/weight-cutting, vegan/vegetarian/plant-based, allergies or other health conditions), high-quality protein supplements may have an important role in providing all the essential nutrients required to optimise muscle growth, in a cost-effective/time-efficient manner.
Dr. Robert Davies is a lecturer in skeletal muscle physiology and clinical exercise physiology in the department of Physical Education and Sport Sciences at the University of Limerick. His current research is focused on the impact of exercise and nutrition on neuromuscular function and muscle protein metabolism’. Contact Robert on firstname.lastname@example.org or view his profile on ORCID or ResarchGate.