Do you keep your race weight down by only packing the bare minimum of snacks? Or do you fill your pockets and pouches until they are overflowing?

Science suggests that there is an ideal amount of carbohydrates an endurance athlete can consume each hour of an event to boost their energy levels without over burdening their digestive tract.

Research suggests the optimum amount as 30-60 grams per hour. This amount is ideal to minimise a negative energy balance and essential to success.

The energy value of this amount of carbohydrates is approximately 4 kilocalories (kcal) per gram (g) of carbohydrates. Therefore, 30 g per hour provides 120 kcal, and 60 g will provide 240 kcal.

The longer the event you are doing, the higher up that range you should aim for as the risk of becoming significantly glycogen deficient is greater.

The required amount is pretty clear – but the ideal format from which to consume that ideal amount is not so definite.

Research suggests that solid food is digested more slowly than liquids, but there is conflicting work in sports nutrition research that indicates that carbohydrate in a gel/drink/bar is oxidised at a similar rate. Although this is probably to do with the protein, fibre and fat content.

In general, sports nutrition foods that are designed for fuelling during exercise are all low in protein, fat and fibre – which is not typical in general food terms – so they are still digested pretty quickly. This would not apply if an athlete was
using standard food in the same way.

For example, a flapjack is high in fat and typically has quite a bit of protein and fibre in it too, so it will work more slowly.

Generally, the higher the intensity of the exercise, the more blood flow gets diverted to the working muscles, heart and lungs, and away from the gut. This tends to mean that athletes will tolerate liquid forms of energy better in high intensity scenarios, such as racing, and will not generally have any issues with having solid foods during steady-state training.

Using Gels

Most gels contain 20-30 g of carbohydrate per serving.

As far as current understanding goes, feeding a little and often seems to be the optimal fuelling strategy, meaning serving sizes of around 25 g are ideal.

Fuelling Your Distance

Distance	Drink/Eat
Short ride and runs of one hour or less	Water. You will use your body’s energy stores (but take back-up containing around 30 g of carbohydrates).
Mid-length ride and runs longer between 1 and 3 hours	For carbohydrate replenishment look to 500ml sports drink/bars/energy gels per hour to provide 30-60 g of carbohydrates.
Rides of 3 hours plus and marathon runs	1 bottle of water and 1 bottle of sports drink per hour at least plus 30-60 g of carbohydrates per hour in total.

Examples of 30-60 Gram Carbohydrate Refills

Depending on your training or event you can find plenty of ways to refill your carbohydrates. Below are some examples.

Food	Stats
Rice Cakes (2)	Calories: 70 Protein: 1.5 g Carbs: 15 g Fat: 0.5 g Fibre: 0.8 g
Peanut Butter & Banana Wrap	Calories: 390 Protein: 11 g Carbs: 56 g Fat: 16 g Fibre: 4 g
Frozen Hash Browns (4)	Calories: 240 Protein: 3 g Carbs: 32 g Fat: 12 g Fibre: 2.4 g
Jelly Babies (Half a 150 g bag)	Calories: 250 Protein: 2 g Carbs: 60 g Fats: 4 g Fibre: 2 g
Dried Fruit Flapjack (100 g)	Calories: 290 Protein: 4.6 g Carbs: 60 g Fat: 22 g Fibre: 4 g
Jaffa Cakes (4)	Calories: 180 Protein: 2 g Carbs: 34 g Fat: 4 g Fibre: 1 g
Boiled Potatoes (3 small)	Calories: 300 Protein: 5 g Carbs: 60 g Fat: 0.5 g Fibre: 6 g
Trail Mix (40 g)	Calories: 170 Protein: 2 g Carbs: 30 g Fat: 7 g Fibre: 2 g
Fruity Malt Loaf (3 slices)	Calories: 312 Protein: 6.9 g Carbs: 66.1 g Fat: 2.1 g Fibre 2.4 g
Pretzels (10 twists, 60 g)	Calories: 228 Protein: 6 g Carbs: 48 g Fat: 1.6 g Fibre: 1.8 g
Dates (50 g)	Calories: 140 Protein: 1.2 g Carbs: 32 g Fat: 0.2 g Fibre: 4 g
Dried Apricots (50 g)	Calories: 160 Protein: 2.5 g Carbs: 41 g Fat: 0.3 g Fibre: 2.5 g
Fresh Figs (3 medium)	Calories: 101 Protein: 0.9 g Carbs: 27 g Fat: 0.4 g Fibre: 4 g
Whole-wheat Pasta (75 g)	Calories: 242 Protein: 9.4 g Carbs: 46.9 g Fat: 1.9 g Fibre: 7.5 g
Microwave Popcorn (50 g)	Calories: 190 Protein: 11 g Carbs: 35 g Fat: 2.2 g Fibre: 6 g
Jam Sandwich (1 slice of white bread)	Calories: 280 Protein: 0 g Carbs: 43 g Fat: 9 g Fibre: 1 g
Marshmallows (6 standard size)	Calories: 140 Protein: 0 g Carbs: 36 g Fat: 0 g Fibre: 0 g
Coconut Water (2 x 330 ml cartons)	Calories: 120 Protein: 0 g Carbs: 30 g Fat: 0 g Fibre: 0 g
Honey (2 tablespoons, 42 g)	Calories: 128 Protein: 0.2 g Carbs: 34 g Fat: 0 g Fibre: 0 g