What Impact Can Sports Nutrition Have On Your Performance?

What Impact Can Sports Nutrition Have On Your Performance?

Evan Lynch ·

As a sport’s dietitian, I come across new athletes every day who are surprised to see the impact a small dietary tweak can have on health & performance, or the potential effect that not engaging in sports nutrition may have. Here at Aid Station, we get it, we understand that ticking the boxes and meeting your nutritional targets can have a huge impact on your recovery, race performance and rate of improvement, in this article, I am going to walk you through some of the different factors in sports nutrition and how they interact with your performance. Let’s get into it.

Carbohydrate Powders, Energy Gels, Chews & Drinks

I felt it would be remiss of me not to start with the carbs, everybody’s favourite macronutrient, I would like to briefly summarise the research base for you to help you appreciate why carbs are so key. It might be helpful to think about carbohydrates as the currency you use to buy performance and high intensity exercise, brass tax, if you intend on cranking out some watts or fast track reps, you are going to need to fund that work with carbohydrates. Generally speaking, the harder you are working, the more you will rely on carbohydrates to fund this work. When you run out of dollars, your capacity to continue exercising will fold, this is commonly referred to as hitting the wall.

What we know to date is that during exercise, the higher the carb intake during training, the better the performance outcome, studies done to show increasing benefits for finish times all the way up to 70g/hr (the equivalent of three small bananas or a sachet of SIS Beta fuel), and that there are steady improvements in how hard exercise feels & muscle damage improving all the way up to 120g per hour (Maurten 320 sachet + 2 gels hourly). As a practitioner, when people ask me “how much carbohydrate should I take on board during a race,” my answer would tend to be as much as physically possible, especially for endurance athletes. Exercise feels about 25% harder in a carb fasted versus fed state.

If you are new to taking on fuel during exercise, practicing with isotonic drinks such as Gatorade, High5 energy or TORQ provides a simpler way of dipping your toe in, from a tolerance perspective, liquids are easier to tolerate than gels, which are easier to tolerate than solids, to get tuned in for your race day nutrition, you may benefit from starting with liquids, building to more concentrated liquids (SIS/Maurten etc.) and then practicing layering on gels, energy bars, chews etc. General targets to aim at for running would be 60-75g/hr, possibly rising to 120g/hr for ultra-runners, and for Ironman triathlons a minimum average of 90g/hr, reaching for 120g/hr on the bike, practicing these targets will ensure you perform optimally, recover well and getting your carbs on board can minimise your risk of gastric distress, maximise muscle protein synthesis and make exercise feel as easy as possible. Practice is very much required with carb products to ensure you can tolerate high intakes and feel confident in your race day plan.


Hydration & Electrolytes

Hydration is a frequently misunderstood topic, with most thinking nailing hydration is simply a case of tanking a pint of water and heading out the door. Hydration is a little more nuanced than this, and has some pretty poignant impacts on you as an athlete. Before we dive into this, some numbers and stats may be helpful for you to appreciate where hydration should lie in terms of importance. To understand these numbers, let’s be aware that 1% dehydration refers to you having lost 1% of your body weight in sweat, i.e. an 80kg man losing 800ml of sweat, if this seems like a lot of sweat, be aware that sweat rates from 500 to 2500ml per hour are considered normal ranges, if you are a heavy sweater, be aware that 1% dehydration results in about a 10% drop in aerobic capacity, and a slight rise in your core temperature, as your body works to cool itself, blood is redirected from your gut to your skin, and gut issues become more likely – meeting this threshold in terms of fluid is easier to achieve than you would think.

Just to note, the perception of thirst or desire to drink does not come about until you are already about 1-2% dehydrated, at which point you are playing catch up. So it is clear that a proactive approach to hydration is needed, aiming to minimise your fluid losses, using products with carbs and electrolytes in them will result in better fluid absorption. Sodium is the second half of this equation, we lose salts in our sweat, if you only replace sweat losses with water, you will further dilute an already reducing electrolyte store, this would be an important fact to consider when we see that 30% of the runners in the women’s marathon in the 2012 Olympics had clinically low sodium levels after finishing. Low sodium levels can lead to respiratory distress, arrhythmia, confusion and at worst a coma. My advice for people looking to nail their hydration would be to opt for isotonic sports drinks to provide optimal fluid absorption and to use electrolyte tablets (bike) or salt sticks (run) to replace electrolyte losses, a hypotonic sports drink after exercise (Lucozade sport lite) will result in superior rehydration post exercise.



Protein products are a convenient way to meet your needs, an athlete needs at least 1.2g/kg, and double that in some cases, depending on what’s going on with an athlete. Meeting protein needs is vital for ensuring muscle tissue recovery post exercise, athletes have the added stress of managing an exercise load on top of normal physiological functioning, not meeting your protein needs will lead to muscle atrophy, injuries, infections due to inability to create white blood cells and possibly even bone density disruption, this isn’t a hypothesis, this is a demonstrated fact. If you struggle to meet your needs, a protein bar, protein ball or protein powder will make your life easier, if you are plant based, a high grade soya protein product will ensure a plant based athlete has a complete protein source to compliment their needs. In some cases, such as ultra events, intra workout protein may be vital to prevent muscle protein degradation and muscle damage (which may cause kidney damage), in such cases the likes of a BCAA or amino acid to add to your bottles may help avoid this fate.


There are a multitude of other supplements in store that can exert a multiplicity of effects, ranging from enhancing your ability to buffer lactic acid (beta alanine) to improved cognitive function (caffeine) and even anti-cramping effects (pickle juice), I will introduce you to some of these supplements over time and the range of effects you can take advantage of to take your performance to the next levels courtesy of Aid Station. Thanks for taking the time to read this article, my name is Evan, and I am the Aid Station dietitian and performance nutritionist, and I am looking forward to introducing you to the interesting and majorly impactful world of sports nutrition, to help you bring your performance up a gear or two.

Happy training, E. 

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