Walking 50 km will burn up calories and it makes sense to eat enough to replace at least some of what you’re using so you don’t feel light-headed and overly tired. The body will use its muscle stores of glycogen and also some of its own fat for fuel, but it makes good sense to use food and drinks to provide some of the fuel during a long 50km walk.
As a rough guide, someone who is 80kg and does the 50km in 12 hours walking will burn up approximately 5,000 Cals. A person who weighs 65 kg will burn about 4,000 Cals. (To convert to kilojoules, multiply by 4.2.) If you have been training for the walk, have plenty of high carb foods the day before and you don’t exercise much the day before, you can expect to have 400-500g of glycogen stored in your muscles. This will provide 1,600-2,000 Cals of stored energy.
High carb foods for the day before the walk could include cereal with fruit and milk for breakfast; sandwiches (or rolls) + fruit for lunch; pasta for dinner; fruit or toast or a smoothie for snacks.
On the morning of the walk, have a bowl of muesli or other cereal, with milk and a sliced banana (about 350-400 Cals). Don’t forget a drink– juice, tea, coffee or water.
You can eat normal food while walking, but avoid anything rich or fatty or your body will want to lie down while you digest it. Carbohydrates are the most easily used fuels and many high carb foods are easy to carry. Small and often will be more effective than trying to eat or drink too much at once. Most people also find it more pleasant if they include some variety with both sweet and savoury foods.
Drinks are important. Thirst is a good guide to fluid needs, so drink whenever you feel thirsty. There’s no need to overdose on water and there’s no need for sports drink if you are eating during the day. However, use sports drinks or juices if you prefer as their sugars add calories. Sports drinks are designed for endurance activity or to give fluids rapidly. They’re especially valuable when the type of physical activity makes eating uncomfortable. They are not essential for walking when you can eat real food.
|Suitable foods to carry||Calories|
|Dried apricots or other dried fruit, 100g||200|
|Nuts, average, 100g||560|
|Trail mix (dried fruit, nuts, seeds), 100g||340|
|Fruit/nut bar, 50g||200|
|Sandwich or roll with filling||250|
|Apple or orange||60|
|Fruit juice, 250 ml||100|
|Savoury crackers, 50g||250|
For a 50 km walk, gels are not necessary. If you wish to use them, make sure you have tried them previously. Gels are designed to give a rapid rise in blood glucose which can be useful when energy levels flag. However, the rise is followed by a rapid drop in blood sugar. Once you start using gels, you really need to continue. If they are used when you have not had enough fluids, they can cause stomach cramps, nausea and vomiting.