Apr 24, 2021 / by Jon Bellis / No Comments

There are lots of excellent books on the subject of nutrition for sport. But there’s also a lot of nonsense on the internet. Some people advocate a way of eating that promotes their philosophy. And others convince you of a nutrition approach that encourages you to buy their product. There is good advice, bad advice and biased advice. But how do you separate the wheat from the chaff? It can seem bewildering.

Every sport is different, and some will have specific and unique nutrition requirements. But for most sports, the same fundamental principles apply. This post explains the key features of a sound sports nutrition approach and provides some basic guidelines to follow.


What are the goals of a nutrition strategy?

There is so much more to optimal sports performance than simply training hard and competing. If you pay little regard to your nutrition, you’re missing a huge opportunity to be better: faster, stronger, fitter, and more agile.

Here’s what you want your sports nutrition to accomplish – you want it to:

  • Maximise your performance in training and competition
  • Facilitate rapid and complete recovery and adaptation to training
  • Optimise body composition for your sport. Most of the time, this would be to maximise muscle or strength,  and minimise body fat, thereby optimising your power-to-weight ratio. There are exceptions to this, but anybody composition target still represents an optimal body composition for a particular sport.
  • Keep you healthy and robust.


Carbs are king

You may have met advocates of the keto diet who espouse a low carb approach for weight loss. And they’ll convince you that keto is the way to go even if you’re not losing weight. They claim that you’ll perform just as well, if not better, than people on a higher carb diet. And that’s all because of ketones, a by-product of fat breakdown. Once your body adjusts to using ketones, you’ll be firing on all cylinders, they say.

That’s not what science says. A low carb diet will encourage you to lose muscle, lower your testosterone and reduce your energy levels. A higher carb diet will do the opposite. But crucially, research has repeatedly shown that performance is compromised when you’re on a low carb diet. Performance is maximised on a high carb diet.


Energy systems

It makes sense. Most sports involve short bursts of maximum effort followed by catching your breath. Think about football, rugby, hockey, squash, tennis, boxing, martial arts, weightlifting, bodybuilding, gymnastics, even climbing and cheerleading. They all require repeated cycles of anaerobic effort followed by recovery. And anaerobic activity is fuelled almost 100% by carbohydrates.

Gymnast on the rings Close up of ball control in football.


Keto advocates will say that you use fat to fuel your exercise. You don’t. You may use fat to recover aerobically from each bout of effort, but the effort itself is fuelled by carbohydrate. And if you’re on a low carb diet, your muscle carbohydrate stores – glycogen stores – will be depleted. Yes, your liver can make carbohydrate via gluconeogenesis, but not at the rate required to fuel your sport.


Fat burning

Even distance runners perform better on a high carb diet. You might think, because distance running is aerobic, they might perform just as well on a low carb diet. But, again, research doesn’t back this up. Studies show that distance runners perform better when they carb load before an event.

Scientists have even done studies on fat adaptation. The idea is that if you follow a high-fat diet for two to three days, you become better at using fat as fuel. And if you become a better fat burner, you will spare your carbohydrate stores and be able to run for longer before fatiguing. The results of these studies are equivocal at best, with most showing no benefit to performance.


So, carbs really are essential if you want to maximise your performance. It doesn’t matter if you’re a distance runner or a rugby player; carbs are king.


How to get your carbs

Carbs come in lots of different forms. There are carbs in fruit, vegetables, whole grains, legumes, dairy, refined grains, sports drinks and junk food. But what is the best choice for fuelling your sport?

Some stars of the sporting world claim you can eat what you like as long as you’re training hard. After all, that’s what they do. This is a myth. You might be able to ‘get away with it’ if you eat ad libitum; in other words, you may avoid weight gain. But you certainly won’t optimise your performance, your health or your body composition.

If you eat junk food, you will be taking in more fat than you need and possibly some harmful additives. At the same time, you’ll be getting a few beneficial nutrients. That doesn’t sound like a recipe for optimal health and performance. And it’s not. You’re more likely to get flabby and ill.

And what about refined grains and sports drinks? Is it ok to have these as carb sources? The answer is: sometimes. Both will raise your blood sugar quickly. This is ok before, during and after your training session but, at all other times, it’s best to avoid them. Regular sugar in the form of refined grains and energy drinks will raise your insulin levels, inhibit fat breakdown and may lead to metabolic dysfunction or type 2 diabetes. Regular exercise will counteract this to some extent, but don’t assume you’re immune to the effects of too much sugar just because you exercise.


Good choices

So that leaves fruit, vegetables, wholegrains, legumes and dairy. And that’s your answer. Most of the time, consume those foods to get your carb sources, especially wholegrains, which are carbohydrate-rich.

A healthy wholegrain loaf covered in seeds and grain kernels. Wholegrain is the best choice for fuelling your sport

Research has shown that low glycaemic foods like these are better for restocking carbohydrate stores and maximising performance. And beware of some of the vocabularies around sugar. You may see some food logging apps classifying fruit as a high sugar food. Fruit may well contain pure glucose, but the fructose and fibre content ensures that almost all fruit is low on the glycaemic index. Keep fruit in your diet; it’s healthy and great for refuelling.

Consuming these foods in abundance to get your carbs will keep you healthy. It’ll keep your physiology, microbiome and immune system in good order.

But just one word of caution. These foods are also high in fibre. If you’re not used to fibre, then introduce these higher fibre foods gradually. Your gut will adjust, but it needs a little time. Increase your fibre intake up to its maintenance levels over several weeks. For important competitions, you may even want to reduce your fibre intake – see below.


What about protein?

Protein is vital for recovery, repair and adaptation. You need enough protein to provide the amino acids required for the repair and building of new muscle tissue. But the sports magazines, especially those dedicated to bodybuilding, would have you believe you need 200g to 300g a day or more. You don’t.

Research shows that an intake of 20 to 25 grammes of high-quality protein in a meal is enough to maximise muscle protein synthesis. Any more than this is simply oxidised – used for energy. Further, once muscle protein synthesis is stimulated, any further protein intake does not promote additional protein synthesis. That means you have to wait a few hours before the next protein feed will stimulate some more protein synthesis.

So, if you’re organised, you can take in protein maybe six times a day. For example, 6am, 9am, 12:30pm, 4pm, 7pm, 10:30pm. That’s it; there are no more opportunities to stimulate muscle protein synthesis. That means 150g should be your absolute maximum protein intake. And if you can’t fit six feeds in, it’s going to be 125g.

Protein is expensive and not always ethically or ecologically sound. Keep your protein intake in check and use your calorie allowance for more carbs. Carbs have benefits for performance and body composition and, in general, come with more health-giving nutrients.


How to get your protein

Not all protein is made equal. A protein that contains all the essential amino acids (EAAs) will be better at maintaining health and building new tissues than one that does not. A protein with all the EAAs is called a complete protein, and one without is called an incomplete protein.

All proteins derived from animals are complete. Meat, poultry, dairy, eggs and fish all contain complete proteins. Some plant proteins are complete. Quinoa, soy products and peas are complete proteins, for example.

But most plant proteins are incomplete. They lack or are insufficient in one or more amino acids. But, because different plant proteins lack different amino acids, you can combine them to make complete proteins. In general (legumes or vegetables) with (wholegrains or nuts) will give you complete proteins. Beans on toast is an oft-cited example.


Choosing protein

Whenever you choose a protein source, make sure it’s lean. In meat products, extra fat is mainly saturated. You don’t need it; it will compromise your body composition and your health. Choose poultry and lean cuts of red meat. Zero fat dairy is a good choice, as is white fish. Fatty fish is an excellent choice for health, so have it a couple of times a week, but don’t make it your go-to protein choice.

You’ll hear people poo-pooing lean cuts and zero fat dairy, saying you need some fat in your diet. Sure, you need some fat in your diet, but you don’t need excess saturated fat. Take away the saturated fat by choosing zero fat dairy, then put some healthy fat back in the form of a sprinkling of seeds or nuts.

Low fat greek yoghurt and berries. When considering utrition for sport, low fat dairy is an excellent choice for protein.

If you’re vegan, you’re going to need to find foods that are rich sources of protein. To be clear, very few plant proteins are as rich as animal proteins. So, you’ll need to do some research and identify relatively protein-rich foods that you like, then make sure, on average, you’re getting complete proteins.

Note that some nuts are rich sources of protein, but they’re even richer sources of fat. If you make nuts your go-to protein choice, you’re likely to get fat. For example, if you were to get your 150g of protein in the form of nuts, it would cost you around 3,500 calories. And that’s before you’ve eaten any other kinds of foods. Eat nuts, but go easy on them and don’t make them your protein staple.


Where does fat fit into nutrition for sport?

Humans are very good at making their own fat. You don’t need to consume fat for energy or energy storage; your body will supply that for you.

There are three main reasons why you need fat in your diet – you need it to:

  • Get your essential fats such as omega 3 and omega 6 fatty acids.
  • Facilitate the absorption of fat-soluble vitamins A, D, E and K.
  • Maintain healthy cholesterol levels, both total cholesterol and cholesterol ratios.

The World Health Organisation issues recommendations for fat levels in the diet that are between 15% and 30%. That means it is regarded as safe to lower fat levels to 15% of calories and still fulfil the functions required of your dietary fat intake.

Compared to protein and carbohydrates, fat has a minimal benefit on performance or body composition. Your best bet is to keep fat intake between 15% and 20%. Research showed that a diet composed of 50% carbs, 35% protein and 15% fat was best for preserving muscle whilst losing weight. You may have noticed that this represents a protein intake higher than what we discussed above. But note that this research was on people losing weight, and only two protocols were assessed – one at 35% protein (high) and one at 15% protein (low). The main point is that 15% fat was optimal for body composition changes.


How to get your fat

There is no physiological necessity for dietary saturated fat. You won’t be able to avoid saturated fat altogether because it’s in healthy plant foods. But you can keep it to a minimum by avoiding large intakes of animal fat.

Instead, choose healthy monounsaturated and polyunsaturated fats. You’ll find these fats in vegetables, whole grains and their oils, nuts, seeds and oily fish. If you’re not a vegetarian, then oily fish is an excellent source of essential fats.

Two whole mackerel on a slate with tomatoes. When considering nutrition for sport, oily fish are an excellent source of essential fats

If you’re consuming foods that are high in fat, such as vegetable oils or nuts, then measure them and ensure their contribution to your overall calorie total is 15-20%.


Your ideal macronutrient ratio

You may have worked out from the preceding sections that your ideal macronutrient ratios are

  • 20-25% protein
  • 15-20% fat
  • 55-65% carbs

If you’re trying to lose weight, then these numbers change a little. You’ll be keeping your protein intake the same, maybe even increasing it. Your fat % will stay the same, but you’ll be aiming to lower your calorie intake. That means carbs have to come down, not because ‘low carb helps you lose weight’ but simply because there is nothing else that can be adjusted.



Research shows that loss of water of around 3% of body weight or more leads to a drop off in performance. So if you stay hydrated, it will ensure your performance is not impacted. Science has also found that when you’re hydrated, the cells of your body swell. And when you’re dehydrated, then shrink. The swelling encourages fat breakdown and muscle growth, whilst the shrinkage promotes the opposite: fat accumulation and muscle loss.

For staying hydrated, a good rule of thumb is to consume 1 ml for every calorie burned. If the weather is hot, then you’ll need more than this.

For rehydration, drinks containing a little sodium are better. Low-calorie isotonic sports drinks will do a good job. But, unless you have sweated profusely, water should be all you need, especially if you are eating too.

For training or events lasting less than an hour, water is all you’ll need to stay hydrated. For events longer than this, an isotonic sports drink may be helpful to keep carbohydrate stores topped up and to optimise hydration.


Eating around training

Although everyone has their preferences, there are some practical rules of thumb:

  • Avoid a large meal too close to training; it’ll just make you bloated, may impact your ability to recruit your core and may slow you down.
  • Avoid light carbohydrate meals 1-2 hours before training. This is when your insulin levels will be highest. If your blood sugar physiology is untrained, you may experience problems. Once your muscles start working hard, they will create a demand on your blood sugar to supply the muscles with energy. If your liver does not respond by releasing replacement sugar into the bloodstream, you may experience a blood sugar low. I’ve seen this many times with trainees who mistimed their carb intake before training.
  • Eat a carb-rich meal earlier in the day and avoid a meal within 3 hours of training. This will top up your muscle energy stores, and you’ll be on the brink of hunger with an empty stomach by the time you exercise, which is ideal. For training first thing in the morning, have a carb-rich meal the night before.
  • If you’re not too caffeine-tolerant, and it’s not banned, take a single caffeine shot around 15-20 minutes before training. This will switch on your nervous system and help you feel more energetic.
  • If you’re taking part in a long training session or an endurance event, a sports drink may be helpful to prolong the time before fatigue sets in.
  • Immediately training is over, a whey protein and carbohydrate drink will optimise muscle energy replacement and kick start muscle adaptations.


Eating around competition

If you have an important competition, you may want to modify your diet in the period before the competition. For example,

  • Endurance athletes may want to carb load before the event. This involves reducing carbs initially and then overconsuming carbs one or two days before the competition. This take advantage of super-compensation, muscle’s ability to store more carbohydrate than usual.
  • Bodybuilders do something similar to endurance athletes, but this time it’s to maximise the size of their muscles.
  • A lot of athletes will wish to reduce their fibre intake prior to competition. This ensures they are not too bloated or gassy at the time they compete in their important event.

Other than this, the same rules-of-thumb apply to competition as they do for training.


The wrap-up

Although there is a great deal of science around nutrition for sport, some principles apply to almost every activity:

  • Consume enough protein to facilitate adaptations.
  • Get plenty of carbs for performance, recovery and energy.
  • Keep fat intake low with an emphasis on healthy choices.
  • Stay hydrated to optimise performance.
  • Adjust eating strategy and timing around training and competition.

Distilled down like this, nutrition for sport becomes relatively straightforward. If you’re not following these guidelines currently, you’ll see improvements simply by making the appropriate changes. You shouldn’t need anything more complex or specific than this unless, or until, you compete at a high level.

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