Fuel to Train

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Julie Conran - Dietitian (MINDI)

Julie shares her nutrition tips in preparation for the Blackstairs Adventure Race
Julie Conran Dietitian

This information is designed to answer some of your questions around what, when and how much you should eat when training for an event such as the Blackstairs Adventure Race.

What to eat before your training session

The main fuel for training is carbohydrate, which is stored in the muscles and liver as glycogen, which the body draws upon for energy. The body is only able to store a relatively small amount of carbohydrate, which is why keeping it topped up is so important.

How long after eating a meal should I wait before going for a run?

Everyone has different levels of comfort regarding eating around training, so it is important to trial what works best for you. In general, allow two to four hours before running or cycling after eating a large meal, to allow time for your food to fully digest. After a smaller snack, 30 minutes to two hours should be sufficient. As a general rule low-GI foods (slow release carbohydrates) are best eaten as part of your main meals whilst training ,as well as moderate amounts of protein and fat, as their energy is released more slowly into the blood stream and will provide you with long term energy.

Should I eat before an early morning training session ?

You should eat where possible before your morning run, especially if it's over one hour in duration. Many people find this difficult, but it is important to 'train your gut' for the big day, especially on longer runs.

There are two morning situations to plan for:

The early riser

If you wake up two hours before your training session, good options include porridge, wholegrain toast topped with eggs, low sugar granola and home-made smoothies.

Straight out of bed

If you prefer to get straight on the road with minimal fuss, try a small snack with quick releasing energy such as dried or fresh fruit, nuts and seeds or a shake.

If you are really struggling to eat first thing, try increasing the carbohydrate portion of your evening meal the night before, as this will be stored in the muscles ready for your morning training session.

What should I definitely avoid eating before a run or cycle?

To provide sufficient fuel, foods should be predominantly high in carbohydrate but you should also eat foods that you're used to, make you feel comfortable and don't feel too 'heavy' in your stomach when you begin exercising. In the two to four hours before a run or cycle, try to limit the following foods as these are well known causes of gastrointestinal distresses such as diarrhoea and bowel upsets.

What to avoid...

On the morning of a big race, how long before should I eat and what should I opt for?

What you eat on the morning of your event should not be different to your fuelling strategy that you have developed during your training. Eat a meal two to four hours before the start of the race, and include a range of foods depending on your taste.

Good breakfast options for the morning of your race may include:

What to eat during your training session

Keeping your energy up and establishing a solid fuelling strategy for long training sessions can be tricky Eating during a run can be a new experience and can feel slightly uncomfortable to start with. It's vital to trial eating strategies during longer training runs/cycles as this will help train the gut to digest carbohydrates while on the move.

How far or how long can I run without refuelling?

For training sessions under one hour there is no need to refuel on the move as long as you have eaten enough to keep your energy up before setting out. For runs over one hour in duration, individuals should practice taking on small amounts of high-GI carbohydrates, which will help top up blood glucose and provide ongoing fuel to the working muscles to help maintain a good pace of running. These easily absorbed carbohydrates also provide important fuel for the brain, which allows the body to keep working harder, especially when muscles begin to tire

What are the best foods to eat on a run or cycle to avoid feeling full?

Sticking to easily absorbed, high-GI carbohydrate options should help you avoid discomfort and nausea during a run or cycle. Where possible, try to include some carbohydrate-electrolyte sports drinks to meet your fuel and fluid needs.

Should I only eat when I feel hungry or should I snack continually during a race?

Don't rely on hunger as a cue to refuel during the race. As a general rule, practice and refine your fuelling during training and find a strategy you're comfortable with. Taking on carbohydrate little and often, for a constant energy supply, is often the most efficient strategy.

As a rough guide, approximately 30-60g of carbohydrate an hour will be your target during a marathon, as the body can absorb this amount and use it for energy on the move. Carbohydrate drinks are typically the most efficient way to meet these targets, alongside good hydration. Carbohydrate gels may be readily available on race day and are rapidly absorbed. Small pieces of banana, cereal bars and jellied sweets also can help to offset hunger.

The following will provide around 30g of carbohydrate - see what works best for you and experiment with quantities during training:

How to recover after your training session

If you're training hard for an endurance race, getting your recovery right is vital for staving off muscle soreness and improving your performance.

When should I be eating after a training session to maximise recovery?

The sooner the better - ideally within 30 minutes after running as your body needs essential nutrients to kick start the growth and repair process after a hard training session.

Is protein or carbohydrate more important for recovery?

Both are critical for full recovery after training. Carbohydrates are the body's main fuel source, and are stored as glycogen in the muscles and liver. As the body can only store a certain amount of carbohydrate, once depleted through exercise these reserves need to be replaced before your next training session.

Protein is vital for the growth and repair of muscle tissue and as hard training depletes the body's stores it is important to refuel with high-protein snacks as soon as possible. Ensuring you replenish stores after each training session can significantly reduce muscle soreness the following day. If you can't face eating straight after a run or cycle, introduce fluids to your recovery strategy.

20g of protein is the magic number that you need to hit to optimise the recovery process after training.

The following snacks will help you reach this target:

If you're watching your weight, how do you balance eating for recovery with continued weight loss? How much should you eat?

It is possible to balance proper recovery after exercise with weight loss - it's just about getting the balance right. Although many of the questions mention carbohydrates, it is important to adjust your daily intake depending on your training. Intake should be higher on 'key' training days and reduced on days with less training. When managing your weight, try to get most of your carbohydrates from low-GI foods at mealtimes, rather than lots of higher GI snacks. These will also keep your feeling fuller for longer. Where possible, eat meals as part of your recovery plan following your run or cycle, instead of adding in extra recovery snacks, which increase your total energy (calorie) intake for the day. This may take more planning to coincide runs with mealtimes.

How to stay hydrated

Staying fully hydrated can be a challenge, especially for those who are training hard for an event like a marathon.

What are the different strategies for staying hydrated during long events?

This takes some planning and a bit of common sense. The overall goal of the hydration strategy is to replace the body's water and electrolytes that are lost through sweat.

A fluid loss greater than 2% of body mass (e.g. 1kg for a 50kg runner) can have a negative effect on performance and can increase the strain on the body. Over hydration can also be a problem in long races like a marathon. Recreational runners drinking large amounts of water at each opportunity can lead to 'hyponatremia' (a dilution of blood electrolytes), which can have serious consequences.

During training, runners should attempt to estimate sweat rates. This is easily done by weighing themselves (in minimal clothing) before and after a run (following towelling down), then subtracting any fluid consumed. Every 1 kg lost is roughly equal to 1 litre in sweat . For example, 1 litre lost from a two hour run would equal a sweat rate of 500ml per hour.

Note: This estimation should then be repeated in hot temperatures as sweat rates can vary greatly in hot conditions.

Once this has been worked out, a basic strategy can then be formed to reduce dehydration during the race. Alongside this, runners should fundamentally listen to their body, and drink according to thirst. The body's physiology is tightly regulated so that when there is excessive sweat loss (affecting blood levels) the thirst mechanism is triggered.

Both of these measures can help runners develop an appropriate strategy to stay hydrated - one size doesn't fit all.

How often should I drink during a run?

Make sure you start your race fully hydrated. Drinking approximately 500ml of water two hours before the race should suffice. This will allow any excess to be passed as urine before the starting pistol.

Just before the start, plan to drink a small amount (about 150ml). During your run, drinking should match sweat losses as closely as possible, taking care not to over hydrate. 150-250ml fluids every two miles might be a good starting point.

What are electrolytes and where can I get them?

Electrolytes are found in the blood, sweat and other bodily fluids and have an important role in maintaining fluid balance within the body. Sodium is the most important electrolyte for hydration, while others include potassium and chloride. Sodium levels in the blood are tightly controlled. Fluid and electrolytes are lost in sweat and therefore need to be replaced. Sodium allows the body to absorb and retain more fluid, thus maintaining hydration. Drinking large volumes of water alone can just pass through you and be lost as urine.

You can top up your sodium levels with sports drinks and gels, which are an easy way to absorb and retain fluid during a long run or race.

Putting it into Practice

Here are examples of foods from the different groups to allow you to base your meals around the macronutrients you require based on your activity level.

Protein rich foods

Animal Foods
ChickenLean beef, lamb or pork
Canned tuna or salmonFillet grilled fish
MilkNatural Yoghurt
Cottage Cheese
Plant Foods
Lentils or kidney beansBaked beans (go for reduced sugar ones)
TofuNuts or seeds- almonds, walnuts, pecans, hazelnuts, sunflower seeds, pumpkin seeds, fax seeds, chia seeds
Soya milkNut butter- almond butter

Carbohydrates rich foods and GI

Low GI – good !High GI – bad ! (unless using as fuel during heavy training)
Brown Basmati RiceWhite Rice
Wholewheat PastaWhite Pasta
Sweet potatoes/potatoes (baked skin on, new)Potatoes fried, chips, waffles
White long grain ricePizza
Wholemeal/Rye/Multigrain BreadWhite bread, Baguettes, rolls etc
PorridgeCornflakes, frosties, coco pops etc
AppleSweets, sugary drinks, chocolate
PearCrackers, biscuits


There are 3 types of fat – mono and polyunsaturated and saturated fat.

Healthy Fats

Monounsaturated fatsPolyunsaturated Fats (containing omega 3)
AvocadoSalmon, mackerel, sardines, herring
Peanut Butter, hummusWalnuts, Flaxseed
Olives, Olive oilFlaxseed Oil, Walnut Oil

Pre training food timing

3-4 hrs before trainingCarbohydrate: Low GI – brown rice, wholemeal pasta, sweet/baked potato Protein: Chicken/Turkey (Lean meat) Good Fats: Handful walnuts/almonds, avocado Protein + Good Fats: mackerel or sardines or salmon
1.5hrs before trainingCarbohydrate: apple/pear/oatcakes/porridge Protein: 1-2eggs, cottage cheese, peanut butter, milk/yoghurt, protein shake
Immediately post trainingCarbohydrate: rice/potato/fruit, cereal, etc Protein: Yogurt/Smoothie/Milk/Protein shake Carbohydrate + Protein: Flavoured milk, cottage cheese sandwich, cereal and milk, fruit smoothie, recovery shake