The potential of protein in active individuals
What better way to show the benefits protein on exercise recovery than putting it to the test with Military personnel. We have enlisted the help of Shaun Chapman who is undertaking a PhD in health and exercise nutrition at Anglia Ruskin University working alongside Dr Justin Roberts. Shaun’s research is exploring the impact of consuming additional protein prior to sleep on exercise recovery, body composition and performance during a period of chronic arduous military training.
Key points
- Protein is made-up of amino acids which form together to make protein, and these provide us with energy and structure for our muscles. Good food sources of protein include chicken, fish eggs and dairy foods
- Exercise increases the demand for protein in active individuals and promotes how we adapt to training.
- We know that exercise increases the rate of muscle protein breakdown (MPB) and muscle protein synthesis (MPS) in the recovery period so that damaged proteins in the muscle can be broken down, remodelled and repaired.
- Most people undertaking moderate amounts of intense training may need to consume a total daily protein intake between 1.2 and 2.0 grams per kilogram of body mass per day (g·kg·⁻¹·day⁻¹).
- It is recommended that we consume a source of protein rich in leucine, such as fish, chicken or milk proteins, in 20-40 g servings every 3-4 hours across the day to optimise MPS in response to exercise.
- Consuming 40 g of protein prior to sleep may further support training adaptations by accelerating the recovery of muscle in response to exercise performed earlier in the day.
What is protein?
Some of the most common and debated topics in the sport and fitness world are around protein. Protein is a key macronutrient and is one of the most popular nutritional supplements on the market, which has received a lot of attention from the scientific community for its role in supporting health and exercise. However, what exactly is protein? How much do we need and how can protein support you with your training?
Protein is one of the three main macronutrients along with fats and carbohydrates. Protein provides us with energy but also the building blocks for our muscles. Protein is made-up of amino acids and there are 20 of these in total. Nine of these are considered “essential” as our body cannot make them, and therefore, we have to provide them through our diet. The other 11 are “non-essential” meaning our bodies can produce these amino acids itself. Foods which are rich in protein include meats, fish, eggs, and dairy foods such as milk and cheese. The recommendation for general consumption is ~0.8 g·kg⁻¹·day⁻¹ (56 g per day for a 70 kg individual) of protein as part of a healthy balanced diet. However, it is generally accepted within the scientific community that exercise increases the demand for protein in active individuals and can support how we recover and adapt in response to exercise. For more information, check out our New to protein article.
The Science behind protein & exercise
Before we consider how protein can help us to adapt to exercise, we first need to understand the basics of protein metabolism and how it can be influenced by exercise. Our body is constantly breaking down protein into the individual amino acids so that new proteins can be made. These processes are termed muscle protein breakdown (MPB) and muscle protein synthesis (MPS) and contribute to the overall balance of protein in the body, termed protein balance. The balance of MPB and MPS is crucial for how we adapt to exercise and training. For example, if we have a greater rate of MPB compared to MPS then we will have a negative protein balance which overtime can lead to a loss in muscle mass. On the other hand, if MPS is greater than MPB then this will equal a positive protein balance which, if done consistently over several weeks, can lead to increased muscle mass and strength.
We know that exercise increases the rate of MPB and MPS in the recovery period so that damaged proteins in the muscle can be broken down, remodelled and repaired. However, food, in particular protein, must be consumed to create a positive protein balance, stimulate muscle growth and to improve exercise performance.
Protein and training adaptations
Research shows that the type of exercise may be crucial for promoting specific training adaptations. For instance, following resistance exercise we typically stimulate MPS in structural proteins within the muscle to stimulate the muscle to grow and become bigger and stronger. In contrast, endurance-based exercise stimulates MPS in proteins which helps the muscle become more efficient in using fat and carbohydrates as a fuel during exercise. The question is “how much protein do we need to eat to support how we adapt to exercise?
We know that MPS is maximised postexercise with the consumption of high-quality protein in servings of 20-40 g. Furthermore, protein foods which are high in the amino acid leucine, such as chicken, fish, and dairy foods are particularly good at stimulating MPS. We also know that MPS is stimulated for 24-48 hours postexercise which means there may be large window of opportunity to maximise how our muscles adapt to exercise.
Generally, research recommends that we consume a source of protein, rich in leucine, in 20-40 g servings every 3-4 hours across the day, resulting in a total daily protein intake between 1.2 and 2.0 g·kg·⁻¹·day⁻¹. Whey protein is particularly effective to consume postexercise as it is rapidly absorbed into the blood and muscle meaning it can rapidly stimulate MPS in the recovery period.
Protein prior to sleep
Recent studies indicate that consuming protein prior to sleep can help stimulate MPS during nocturnal sleep and could further support how muscles adapt to exercise. For example, consuming additional protein in the recovery period in the hours after exercise and/or 30-minutes prior to sleep can reduce muscle damage and soreness in the initial days and can help restore muscle function in less time when compared to those who consume no protein. In this instance, casein protein may be more advantageous due to it being a slower realising protein due to its slower digestion in the gut. The slower digestion of casein protein means that it is absorbed more slowly into the blood and muscles and produces a steady, sustained rise in MPS throughout the night. Casein is mostly found in dairy products such as milk, cheese, and yoghurt.
You can learn more about Shaun’s research via his University and twitter page:https://twitter.com/shaunchapman12 & https://aru.ac.uk/people/shaun-chapman
