Food and nutrition is an undeniably important tool in sport, there is no debate on this. The ins and outs and dietary specifics is however a different matter and sparks much debate. Truthfully, although we can establish general foundations, the best way to eat for performance and recovery is likely to be somewhat individually based.
Why bother with nutrition?
Adequate nutrition when we are engaging in regular sport is crucial to repair damaged muscles, to condition these muscles (what a gym goer might call ‘gains’) and to support our immune system. I emphasise the immune system as any appropriately designed sports nutrition protocol should consider this. The muscles and performance is of course important yet if you are regularly falling sick and unable to train, there is little point in considering anything else. Bottom line, if you want to perform well and to continue performing well, nutrition is key.
The Basics. Energy, Carbohydrate, Protein, Fat, Vitamins & Minerals, Hydration.
We need an appropriate amount of calories to sustain our exercise regime and for those who do not wish to lose body fat, energy intake should equate energy burnt. Seemingly an obvious statement however often not given full credit due. If our energy intake is not adequate we are at risk of losing muscle mass, falling sick, impacting bone mineral density and messing with our hormones.
It is difficult to give specific numbers on general platform however, as a 50-100kg athlete (training 2-3 hours daily, 5-6 days a week) you are possibly looking at around 40-70 kcals/kg/day. You can see how this number hikes up when you compare to someone with a more ‘normal’ level of activity (30-40 minutes daily, 3 times per week) who is likely to require around 25-35 kcals/kg/day.
I still feel as though carbs are sometimes demonised, or if not demonised, at least not viewed as so important. Let me tell you, carbohydrates are an essential component of sports nutrition (and not to mention everyday life).
Why so important?
1. They are utilised by the body as its preferred fuel source – they give us energy
The carbohydrates we consume in our diets exist as long chains which are broken down during the digestive process to release individual sugars. Glucose is one of these sugars and is the predominant fuel utilised to kick-start cellular energy production.
When glucose is not immediately required to provide energy it is stored in the form of glycogen, primarily found in the liver and skeletal muscle cells. This stored glycogen provides a source of energy to burn when undertaking exercise.
2. They are essential for exercise recovery
Replenishing glycogen stores which are burnt through exercise is a critical part of recovery. The human body is a weird and wonderful thing and actually sets out to help us achieve this. How so? By increasing our sensitivity to insulin post-exercise.
Insulin is a storage hormone, helping to transport glucose into cells where it can be used to produce energy. By becoming more sensitive to insulin we are better able to transport glucose into cells and thus better able to replenish glycogen stores, enabling us to recover from exercise more efficiently and effectively. In the absence of carbohydrate intake this enhanced insulin sensitivity is lost.
How much carbohydrate should I be eating?
Again, specific figures are difficult to provide on a general platform. As follows for most people, the breakdown of macronutrients should be around 45-55% carbohydrate, 15-20% protein and 25-35% fat. Quantities within these ratios will differ depending on activity level. For example, those lightly exercising (or not at all) usually require between 3-5g of carbohydrate/kg/day. Athletes may require between 5-8g/kg, whilst those training even more intensely might require 8-10g/kg.
Generally, in the first 4 hours of intense exercise recovery it is suggested that an intake of 1.2g of carbohydrate/kg/hour is optimal for the repletion of muscle glycogen. Reducing carbohydrate consumption to 0.8g/kg/hour and combining this with 0.2-0.4g/kg of protein per hour has also been seen to optimise muscle glycogen repletion (whilst being somewhat more manageable). As a very general rule of thumb you are looking at an approximate 4:1 ratio carbs to protein.
When we think about protein we often refer to a positive or negative nitrogen balance. Why? Because protein sources contain nitrogen whilst carbohydrate and fat do not, meaning we can use this as a measure of adequate intake. Negative nitrogen balance can lead to breakdown of protein and slow recovery, eventually meaning we are at risk of muscle wasting, illness and injury.
For a person training lightly or not at all, 0.8-1.2g of protein/kg/day is deemed sufficient. For an athlete (particularly those weight training) this can reach well over 2g. In order to optimise muscle protein synthesis, it is suggested to spread protein intake throughout the day in 20-40g servings, including each of the essential amino acids as well as a decent serve of leucine (optimal protein serving size will vary depending on factors such as age and exercise undertaken).
Recommendations for fat intake are similar between athletes and non-athletes (25%-35% of the diet). Essential fatty acids are a must within this as they cannot be synthesised by the body, whilst enough fat in the diet generally is important to maintain fat stores within muscles (an alternative energy source).
Vitamins & Minerals
There is very little evidence to support vitamin and mineral supplementation as an ergogenic aid. However, we do need to ensure that intake is adequate in order to maintain overall health. As said earlier, if we are falling sick and unable to train the knock on impact on our muscles and performance is huge.
A well planned diet should be able to meet all of our needs with the possible exception of vitamin D (particularly in the UK winter) and iron for those at risk of anaemia (commonly women, vegetarians and vegans).
Points to address to support the immune system:
Energy intake. If you are not consuming enough energy, it is highly likely you are not consuming enough nutrition.
Exercise recovery. This should include adequate carbohydrate, protein and rest, as well as a consideration of essential fatty acid intake. An appropriate combination of all of these is crucial to ensure we do not fall sick.
When you have considered the above, look at the diet more closely for individual nutrients which may be lacking.
Consider gut health and the microbiome. We are beginning to understand the complex relationship between the bacteria in our gut and the functioning of our immune system. Dietary choices can impact the health of our gut microbes (and thus our immune system) and should therefore be considered in a training protocol.
Not to be forgotten. Being dehydrated can significantly impact performance with as little as 2% loss of body weight having an effect. Working closely to monitor sweat loss/body weight before and after exercise can help to establish how much fluid to take on board.
So there you have it, a whistle-stop tour through the basics of sports nutrition. These principles are relevant to all of us, whether you are a dog walker or a marathon runner, we all need to refuel appropriately (what will differ is the definition of appropriate). With the rise of ‘normal’ people incorporating tough training regimes and gym sessions into their everyday lives, understanding how to properly fuel ourselves is crucial to overall well-being, let alone smashing your personal best or running that extra mile.
Beelen, M., Burke, L.M., Gibala, M.J. et al. (2010). ‘Nutritional Strategies to Promote Post-Exercise Recovery’, International Journal of Sport Nutrition and Exercise Metabolism, 20(6), pp. 515-32. [Online]. Available at: www.ncbi.nlm.nih.gov
Belkaid, Y., & Hand, T. (2014). ‘Role of the Microbiota in Immunity and Inflammation’, Cell, 157(1), pp. 121-141. [Online]. Available at: www.ncbi.nlm.nih.gov
Kerksick, C.M., Wilborn, C.D., Roberts, M.D. et al. (2018). ‘ISSN exercise & sports nutrition review update: research & recommendations’, Journal of the International Society of Sports Nutrition, 15(1). [Online]. Available at: www.ncbi.nlm.nih.gov
Thank you so much to the guest writer, Molly Hodgen. She is a fantastic nutritionist in Bishops Stortford and you can find out more about her services at her website: https://www.mollyhodgen.com