GB Cross country athlete and Sports Nutrition MSc Emily Hosker-Thornhill shares advice on fuelling your training and racing to reach your potential.

With so many articles highlighting the issue of RED-S, I feel like a lot of athletes are confused about what they should be eating to help fuel their performance and their running.

Having a great nutritionally balanced diet will really help you get the most out of yourself, your performance, your growth, happiness, health and ultimately longevity in the sport. Whether you’re a fun runner that trains a few days a week, or you’re an elite GB athlete, your nutrition is equally important. A wise man once told me, “well Emily, you wouldn’t put p*ss in a Ferrari”, so that’s what I’m going to tackle today.

It’s all about real foods, that real athletes eat, to get the best out of our performance. What I’m really trying to get across, is that as athletes, we need to nourish our bodies, look after them, and fuel them with the best foods/nutrients/ingredients possible.

These are my top five pieces of information that hopefully will be useful for all athletes, whether you’re young or old, big or small.

Fuel up before races and training!

You can’t perform to your best on an empty stomach. You need to fuel your system to get all cylinders firing! A lot of pre-race or pre-training foods are usually whatever works best for the athlete, so don’t be afraid to experiment and try different things. All the ‘top dogs’ in sports nutrition are consistently saying that we need carbohydrates to perform. Carbohydrates are the best fuel pre-run because we store this as glycogen in our liver and our muscles. This is what we use up during training or races. When you ‘hit the wall’, this is when your glycogen stores are running out.

Some really good pre-race/training foods are things like bagels with peanut butter, jam or honey, banana, porridge (really good mixed with a mashed banana in it), thick/scotch pancakes (I love them with syrup mmmm), toast with jam, PB or honey, Soreen and cereal. These foods are high in carbohydrates, filled with quick releasing sugars, and easily digestible.

If your race is a little later in the day, having something like eggs or beans on toast, as a first breakfast, is perfect, as it has both protein and carbs to keep you going. Sticking with white bread or bagels is usually a bit easier on the digestive system and should help if you find yourself visiting the toilets often.

If like me, you’re up early in the morning for a run, something as quick and digestible as a banana with some peanut butter on it is a great quick release of energy that sits well on your tummy.


A lot of athletes really like to use protein shakes/supplements to recover. And whilst these definitely have a time and place in athletes’ diet, there are also other things for those of us who don’t use them.

Each time you exercise, your body breaks down muscle fibres, and depletes glycogen stores. To help rebuild your muscles it needs proper nutrients and lots of them. General rule of thumb is that you have a 30-minute window to eat something after you’ve finished running to get the best recovery. (No you won’t recover less if you’re on 31 minutes!).

During this time, you need carbs and a bit of protein, usually around a 4:1 ratio. Too much protein and you won’t absorb the carbs as well, too little and you won’t have enough amino acids.

So, what are you meant to have? Well luckily nature has made the perfect product for you: milk! And an even better version for runners; chocolate milk! Having a chocolate milk post training session, long run or race is one of the best things you can have to refuel. It has the absolute perfect balance of carbohydrates to protein in it, it’s full of electrolytes to help replenish those salts you’ve sweated out, and its full of vitamin D, calcium and potassium.

Top Tip

Invest in one of those vacuum insulated, thermos, stainless steel bottles (loads are on Amazon). Mix up your chocolate powder (like Nesquik) and milk before your training and use your new bottle! Keeps the milk fridge temperature for ages, even in the summer.

After your chocolate milk, it’s always good to then try and get a meal in ASAP after your training or session. A bigger window of 90 minutes is usually a good rule of thumb for this. Having a balanced meal of protein, carbs and veggies afterwards, will help top up the glycogen stores even more, and help you recover faster, as you’re providing the body with essential nutrients.



Stick to wholesome foods

This is really about eating foods that are actual foods, if that makes sense? So out there in the supermarkets there are so many different options and varieties of everything, like low fat cheese, low fat yoghurts, low carb bread and an abundance of ‘lite’ foods. It drives me bonkers.

A lot of these foods are missing out vital ingredients, full of artificial colours or flavourings, additives and preservatives which are just junk and doing no favours for your body. Low fat cheese is essentially just cheese from skim milk, so you’re missing out on all those nutritious fats (and flavour). Low fat yoghurt is just sugar flavoured milk essentially, and full of sugar and I bet the ingredients list takes up the whole pot. These ‘lite’ products are generally not nourishing, and as an athlete it’s not doing you any favours.

Go for food that is actually food! Real live yoghurts (such as Yeo valley) are so good for you because they have calcium, vitamin D, protein, and live cultures in them which are great for the digestive system and intestinal health. I always think cheese is a bit of an unsung hero, as it’s full of calcium, protein, magnesium, potassium, vitamins A, D and K, and actually offers protection for dental caries!

Keep it simple

A good go-to rule is if you’re buying foods or products in the supermarket, go for items that have around five ingredients or fewer. Equally if you can’t pronounce an ingredient then it’s probably not going to be great for you. An example of this is things like jarred pasta sauces, (if you can’t make your own) go for ones that are just a few ingredients. Same with yoghurts, breads, sauce, cereal bars or anything really.

Obviously, there are some foods which yeah, have a lot of ingredients, and that’s cool. But generally, a good way to get good wholesome foods is around five ingredients or less!

Replace those electrolytes and keep hydrated

Now that we’re coming up to summer, electrolytes are going to be lost faster! The electrolytes, sodium and potassium, are crucial in regulating your bodies water balance when you’re exercising or competing. They allow your muscle cells, and other cells in your body, to retain the right balance of water. When we sweat, we lose electrolytes, that’s why your sweat is salty!

Water is essential to maintain blood volume, allow muscle contractions to take place and regulate body temperature. As we get dehydrated, there is a reduction in performance, both physically and mentally. Heart rate, body temperature and perception of effort increases when we’re dehydrated, especially when we exercise in the heat. So it’s really important in these summer months to stay on top of it!

Regarding racing or training, if you’re doing a 5k or less, it’s not really going to affect things too much, but anything longer it can affect performance. Things like sports drinks or hydration tablets are a good way to get the salts you need quickly. It’s worth noting if you’re running on holiday in a warmer climate or at altitude, it’s worth adding hydration tablets/drinks into your routine on those bigger training days. Try and keep on top of hydration throughout the day and aim to keep your pee to a light straw colour!

Balance is key

I always say everything in life is a balance. You can’t live your life as a super serious strict athlete or you won’t enjoy it. You can’t be so focused and dedicated that you can’t see your friends or do anything fun. Equally you can’t only eat ‘healthy foods’ all the time, because let’s face it there are too many tasty options to miss out on.

Life is always about enjoyment! Athletes always perform at their best when they’re happy and healthy. Never restrict anything from your diet, there is simply no need. Tasty food is there to be eaten and enjoyed. If you’re eating three good meals a day, some good snacks, having your 5-a-day, and generally eating pretty well, then that’s good going! I’m certainly never going to feel guilty about having some chocolate, it’s too yummy, and life is far too short to not eat chocolate.

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Emily Hosker-Thornhill has a BSc in nutrition and an MSc in Sports Nutrition so knows her stuff. The GB Cross Country athlete shares advice on Instagram so if you like the cut of her jib then get following.