My 10 Rules of Performance Nutrition
In today’s social media driven world, there’s so much information coming at you that it’s hard to know whats is true, and perhaps more importantly, what is relevant to you.
That’s certainly true for nutrition, not least performance nutrition.
My aim with this article is to remove the frustration of wondering what - out of all the information out there - is useful and relevant to your goals.
In order to do that, I want to give you ten key principles that you can focus on to optimise your body composition, health, and performance as an athlete.
1. Meet Energy Demands
As obvious as it sounds, you can’t expect the body to continue outputting high levels of training and competition if you don’t give it the fuel to do so.
In fact, if you continue to do this, not only will your performance and recovery suffer, but you’ll also put yourself at risk of what’s known as Relative Energy Deficiency in Sport (R.E.D.S.).
This can occur when the body starts to down-regulate essentially bodily processes as a result of you continuing to output high levels of activity without providing adequate fuel.
In other words, the body recognises you’re stubborn enough to keep training in spite of not giving it sufficient energy to do so, so it takes the energy from elsewhere.
That could be from systems that effect your immune function, bone health, cardiovascular health, gut health, reproductive health (e.g. females losing their monthly period), and growth and development in the case of young athletes.
On the flipside, there is such a thing as overfuelling.
That is, if you give the body more energy than it needs for training and everyday life, the extra energy will be stored, predominantly as body fat.
Of course, if you’re wanting to gain muscle, weight gain can be beneficial, but that can easily be taken too far to the point of gaining more body fat than muscle.
Alternatively, you might want to be in a energy deficit if fat-loss is your goal.
In that case, keys to avoiding R.E.D.S, include avoiding severe energy deficits, constraining the duration of your fat-loss phase, periodising your fuelling around the training and competition period, and ensuring the rest of your nutrition is as on point as possible.
2. Carbohydrates Fuel Hard Training and Competition
Once you have your overall energy balance in a good place, you can look at where those calories come from - that is, the macronutrient breakdown of the calories that make up your energy intake.
The first of those we’ll consider is carbohydrate.
Carbohydrates come from sources like rice, pasta, potatoes, oats, breads, fruits, cereals, as well as sugar-containing foods.
When we consume carbohydrate-containing foods, they’re broken down into glucose, and that glucose circulates around the blood, where if it is not used right away, is then stored as glycogen, mainly in the muscles and liver.
This glycogen will then remain stored until it is required, either for everyday tasks, or more importantly, in the case of high-intensity activity where it is the predominant and preferred fuel source.
We can use this knowledge to our advantage by consuming sufficient carbohydrates on an ongoing basis, and potentially also biasing intake of them around training periods, as we’ll discuss later.
A general recommendation is to consume 3-6g of carbohydrate per kg of bodyweight per day for athletes.
Even with this large range, many athletes’ intake requirements will fall outside of it based on individual physical characteristics, preferences, and training loads.
3. Protein Provides the Building Blocks
The second macronutrient we’ll look at it protein.
The first thing to consider is that your muscles (and other bodily tissues) are protein-based structures - That is, they’re made of protein.
That protein is in a constant state of flux, being broken down and built up throughout your daily life.
You increase the breakdown of those tissues during training, but you also put a stimulus on the tissues to adapt and grow.
By providing sufficient protein on a ongoing basis, you’ll decrease the protein breakdown side of that equation, and support the protein synthesis side, leading to improved recovery and muscle adaptation.
The general recommendation for athletes is to consume 2g of protein per kg of bodyweight per day, preferably spread across 3-5 meals.
This can be consumed through sources like meat, chicken, fish, eggs, tofu, milk and other dairy products.
4. Healthy Fats are Essential
The topic of fat intake has been controversial for decades.
It’s gone from being demonised as a major cause of ill-health to celebrated by those promoting a ketogenic or carnivore diet, for example.
By looking at the scientific evidence, it’s becoming clear that the answer is likely somewhere in the middle, and that the source of those fats is probably a bigger determinant of their effect on health.
Take the Mediterranean diet for example, which is commonly (rightly) cited as one of the healthiest diets.
It’s relatively high in fat, but relatively low in saturated fats.
That’s not to say that you shouldn’t have any saturated fats in our diet, but it still should give you some clues, especially when you compare The Mediterranean to diets high in saturated fat, and observe the negative effects of that.
Regardless, we still know that having some fat in our diet is essential.
One example of this is that Omega-3 fatty acids can’t be created by the body (unlike many other nutrients, which can be made from combining other nutrients).
These therefore need to be consumed through food (or supplemented) in order to meet baseline levels and avoid the downsides of deficiencies.
Even outside of that, fatty acids are required for creation of the structure of the cells in our body, the creation of our body’s hormones, and in the absorption of fat-soluble vitamins.
And let’s be honest, your diet would become pretty bland and boring without any fat.
My general recommendation with fat is to consume somewhere in the range of 0.75-1.25g per kg of bodyweight per day, aiming to get most of that from unsaturated sources like oils (e.g. olive oil), nuts, seeds, avocado, and fatty fish, which also allowing some room for saturated fat that are within the other foods you’re eating (meat, dairy, etc.).
5. Fibre, Fruit, and Veg are Critical to Health
It’s no secret that fruit, vegetables, and other fibre-rich foods are “good for you”.
But it can be difficult to know what that actually means.
And I’ve noticed that that lack of clarity can lead to athletes (and people in general), not taking their intake of these foods seriously, and therefore not getting the benefits.
There are many aspects of these foods worth exploring, and I will do so in other articles, but the main important aspects as I see them are (a) Fibre and (b) Micronutrients (vitamins, minerals, and phytonutrients).
Fibre is crucial for digestive health, helping to regulate bowel movements allowing for efficient excretion of the waste products of digestion.
But that’s not all it does.
Fibre also provides the food for your gut microbiota - the tiny living microorganisms in your gut.
The by-products that are created by these microorganisms consuming fibre are known as short-chain fatty acids.
Without going into too much detail (I will do in future articles), these short-chain fatty acids are involved in a wide range of health and performance related outcomes, including immune function, cardiovascular health, inflammation regulation, and even mental wellbeing.
For athletes, this means better nutrient absorption, reduced illness, reduced disease risk, and improved recovery.
Micronutrients (vitamins, minerals, and phytonutrients) are involved in virtually every process in the body.
They support energy production, bone health, immune function, muscle contraction, and the reduction of oxidative stress from training.
For example, iron is essential for oxygen transport in the blood, calcium and vitamin D support bone density, and antioxidants help combat the inflammation caused by intense exercise.
Without adequate intake of these nutrients, you’re likely to experience fatigue, increased injury risk, slower recovery, and compromised performance, even if you're hitting your macronutrient targets.
In terms of recommendations, the good news is that by consuming a variety of colourful fruits and vegetables, along with whole grains, nuts, seeds, and legumes daily, you're likely cover your bases for both fibre and micronutrients - I’d recommend 5 portions of fruit and veg and 5 portions of other fibre-rich foods daily in this case.
However, having a specific fibre intake target (E.g. 10g per 100 kcal) might be a useful addition if someone is already tracking their food intake, and there are cases where it might be appropriate to assess the intake of specific micronutrients, or even testing blood markers to assess for potential deficiencies.
6. Fluids Keep Things Flowing
Your body is made up of over 50% water.
We lose water on a daily basis and throughout training through sweating, urination, and breathing.
If that leads to as little as 2% bodyweight loss (e.g. 1.5kg for a 75kg athlete), athletic performance becomes negatively effected.
Considering an hour of exercise could easily lead to a 1.5 litre (1.5 kg) loss of sweat, it shouldn’t be surprising how important it is to stay on top of fluid intake in order to avoid dehydration.
This is important because of how your hydration levels effect how your body works.
In simplistic terms, I like to think of water as keeping things flowing in the body.
That could refer to the effect is has on blood viscosity (how thick it is), where dehydration can lead to the blood becoming thicker, making it harder for the blood to pump the blood, and therefore how efficiently nutrients and oxygen can get to the working muscles and brain, and how efficiently waste products can be removed, both which will have a massive impact on physical and mental performance.
Less fluid also leads to less sweating, which can have negative effects on performance, given the cooling effect of sweating.
The 'flowing' analogy also applies to joints, which rely on synovial fluid for lubrication and cushioning between bones - the body’s ability to create this fluid depends on having sufficient fluid.
It also extends to digestion, where dehydration can cause constipation, leading to discomfort, bloating, and impaired nutrient absorption.
Dehydration also affects and is affected by electrolyte status in the body, which plays a critical role in fluid balance, nerve function, and muscle contraction.
In terms of recommendations, there will obviously be a lot of individual variation, but most athletes will benefit from consuming 2.5-3.5L per day.
That said, my preferred recommendation for daily fluid intake is to “drink to thirst” or better yet “drink to avoid thirst”.
This makes use of the body’s in-built mechanism to avoid dehydration, and in doing so, takes into account your individual requirements, varying environmental conditions like heat, and fluctuations in training loads.
In addition to that daily recommendation, I recommend that athletes be more specific with hydration around the training/competition window, aiming to consume an equal or greater amount of fluid in the peri-performance (before, during, and after performance) period to what is lost during that performance period.
That means that if you are losing 1.5L of fluid (measured by bodyweight loss) during a training session or competition, you should aim to consume that amount throughout the peri-performance period.
For example, that could mean 500ml in the 30 minutes before training, 500ml during, and 500ml afterwards.
If the exact numbers feel overwhelming or you don’t want to go through the process of finding out your numbers, you can simply focus on ensuring adequate daily hydration (drink to thirst) and add to it by getting in some extra fluids before, during, and after training sessions and competition.
7. Carb-Loading Superfuels the Tank
I’ve already spoken about the role of carbs, how consuming carbs leads to increased glycogen stores in the body, and how that glycogen is the preferred source used in high-intensity activity.
In addition to moderate-high ongoing carbohydrate intake, you can make further use of this knowledge by increasing carbohydrate intake in the day or days prior to competition.
This short-term increase will result in the body increasing it’s ability to store glycogen, and the extra carbohydrates provided will then be stored and available on competition day.
This is especially important for events like a marathon, where glycogen depletion can become the defining factor effecting whether someone succeeds in hitting their goal time or even finishing the race.
But even in sports where competition isn’t long enough for glycogen to become near depletion levels, like a football match, it can still be beneficial to go into the match with high levels of glycogen, ensuring ample supply of fuel for that match.
This could be as simple as adding an extra portion of carbohydrates to each meal in the day or days leading up to the event.
If you want more accuracy, aiming for somewhere in the range of 6-10g of carbohydrates per kg body weight per day in the days or days leading up to the event is a good general target.
That target should be towards the higher end in terms of grams and days if the duration and intensity of the event is on higher, and towards the lower end for shorter and less intense events.
As an example, a GAA player might aim to hit 7g per kg of bodyweight the day before a match (e.g. 525g for a 75kg athlete), but a marathon runner might aim to hit 10g per kg of bodyweight for the 2 full days leading up to the event.
8. Pre- and Intra-Training Nutrition Gives an Extra Boost
You can extend the benefit of carbohydrate intake even further by providing more in the period immediately before and during the training session or competition.
In this case, the idea isn’t so much to increase glycogen storage (since this process can take a few hours), but more so to provide an immediate source of glucose to be used, such that the use of the stored glycogen is reduced, thereby delaying the point at which fatigue sets in due to depleted glycogen.
Again, this becomes more important in longer, more sustained sports like distance running, which is why you’ll see the focus on consuming energy gels and the likes during races.
But it can also be useful in shorter duration sports, where carbohydrate consumption seems to also work through mechanisms other than simply fuelling.
That’s exemplified in studies showing that even just swirling a carb drink on your mouth, without swallowing, and therefore without it providing extra fuel, can have a performance benefit.
For these reasons, it can be worth experimenting with consuming up to 60g per hour of activity during the period before and during the event.
As opposed to ongoing carbohydrate intake, which I’d generally recommend coming from mostly complex carbohydrate sources (usually whole foods), you’ll benefit from focussing your carbohydrate intake around more simple carbohydrates or high-GI carbohydrates during the intra-performance period.
This can include sources like sports drinks and energy gels, but could also include food-based sources like fruits, fruit juices, sugary sweets, and highly-refined starchy foods like bagels, rice cakes, and cereals.
9. Post-Training Nutrition Kickstarts Recovery
Recovery isn’t confined the period immediately after training or competition.
You’ll know that if you’ve ever woken up sore the day after a tough training session.
That means that your recovery period is usually the total time between the end of one session and the start of the next.
If your nutrition doesn’t reflect that through consistent intake of sufficient calories, protein, and micronutrients, no amount of focus on the post-training period will solve your recovery issues.
With that said, it logically and logistically makes sense to optimise your post-training nutrition as much as possible, given that’s when the body will be most in need of supportive nutrition.
The main principles of recovery nutrition can be summarised as three Rs: Repair, Replenish, and Rehydrate.
The repair component focuses on protein intake to support muscle recovery and growth.
During training, muscle fibres experience damage and breakdown.
Consuming protein in the post-training window provides the amino acids necessary to stimulate muscle protein synthesis, facilitating the repair and rebuilding of muscle tissue.
Without adequate protein, the body may break down protein from other areas to support recovery, which can compromise overall muscle maintenance and adaptation.
Replenishing refers primarily to restoring glycogen stores through carbohydrate intake.
High-intensity training depletes the carbohydrates stored in your muscles and liver.
Consuming carbohydrates after training initiates the refuelling process, which is particularly important if your next session is within 24 hours.
There's also evidence that the post-training period offers a window of enhanced insulin sensitivity, meaning carbohydrates consumed during this time may be stored as glycogen more efficiently.
The third R, rehydration refers to replacing the fluids lost through sweat during your session.
Proper rehydration is crucial not only for replacing what was lost, but also for supporting the recovery process itself.
When you're adequately hydrated, your blood flows more efficiently, delivering nutrients to working muscles and removing waste products more effectively.
Dehydration, on the other hand, increases blood viscosity, which can slow recovery and impair adaptation from training.
In practical terms, a meal or snack containing both protein and carbohydrates within 1-2 hours after training, alongside adequate fluids, will allow you to tick those three boxes.
This could be a chicken and rice bowl with vegetables, a smoothie made with protein powder, banana, and berries, Greek yoghurt with granola and fruit, or even a chicken sandwich with a glass of milk.
10. Food First, But Not Food Only
Focussing on supplementation without addressing the areas we’ve already talked about is likely to be a waste of time and money.
But if you have your overall nutrition in a good place, supplements can certainly be of benefit.
I tend to think of supplements as falling into two categories: Food Supplements and Performance Supplements.
Of course there is some crossover, but for the most part, food supplements provide nutrients that can be found in food and are necessary for the body to function, but which you struggle to get in through food alone, or just find more convenient to get through supplements.
This includes protein powder, carbohydrate powders/gels, electrolytes, fish oils, vitamins (e.g. vitamin D) and minerals (E.g. Magnesium).
Performance Supplements are generally not necessary for normal bodily function (for example, not taking them wouldn’t risk nutritional deficiency), but rather than can provide a performance boost above what food alone can provide.
This includes caffeine, creatine, beta-alanine, sodium bicarbonate, and other more advanced supplements.
Out of any section, supplementation tends to be the one that requires the most individual approach so I can’t provide a complete list here.
But I will say that for most athletes, protein powders can be useful in allowing you to hit your daily protein targets, carbohydrate supplements can be useful in and around the training/competition period, fish oils and vitamin D can be useful for most of us who don’t get enough sunlight or eat enough oily fish, and creatine can be beneficial to most sporting goals that require high-intensity outputs.
After reading all that, you’ll be somewhere on the scale of completely overwhelmed to feeling happy that you’re nailing your nutrition.
If your towards the lower end, great!
You’ve been surviving without having your nutrition in check, so the only way is up - I’d recommend you start with the first point, and work through them in order over the coming weeks and months.
If you’re towards the higher end, that’s also great.
You can feel confident that you’re doing most of what needs done from a nutritional perspective and can continue to do so, whilst also continuing to look for further areas of improvement.
Article Written By Conor O’Neill
P.s. You can find out more about Performance Nutrition Coaching HERE.