When participating in Endurance events such as half and full marathons, triathlons, distance cycle rides or even just extra long training sessions, it’s important to master your food intake. It would be simple to provide a list of foods and times of when to eat, but firstly, it helps to understand how the body works under an endurance effort.
Energy can only be used by the body in the form of glycogen, a simple carbohydrate (a form of sugar). And the body can store up to 2000 calories worth of glycogen within the muscles and liver for it to be readily available, which is why you can jog for over an hour or so without needing food. To use body fat as energy requires it to be converted to glycogen first, this is a slower process.
Depending on your intensity, the body burns amounts of body fat in conjunction with carbs. However, body fat needs a lot of oxygen to burn, therefore the lower the intensity, the more aerobic the exercise, the more oxygen is available and the more fat in comparative ratio to carbs is being used. This is because the body has an opportunity to convert that fat to energy due to the lower intensity. At high intensity, there is no spare oxygen and the body will draw from much of the glycogen stores within the body. For those with a weight loss goal, it would be easy to have an ‘aha’ moment and surmise that you’ll burn more body fat if you work at a lower intensity, but that’s only the ratio of fat to carbs, you’ll still burn more fat with higher intensity over time. It was this fact that spawned the misleading ‘fat burning zone’ to be plastered over cardio machines in the gym. It’s a myth, pay no heed.
So whilst pre-exercise nutrition is supremely important to ensure that those glycogen stores are full before you commence exercise, long periods of endurance training require extra sustenance. If the body’s glycogen stores become depleted, then the body needs to convert more body fat for energy. As previously discussed, this takes more oxygen, to do this you will slow down and feel lethargic. This is commonly known as ‘hitting the wall’. A regular intake of water, electrolytes, essential nutrients and energy in the form of readily available calories can maintain this delicate balance and ensure maximum output over a longer period of time.
This is the where the use of exercise gels and sports drinks can be popular. The requirement for water changes depending on intensity and heat, but you can bank on needing at least a litre per hour during endurance exercise. Sports drinks such as Powerade are designed to balance the water requirement with the correct amount of electrolytes (essential minerals) and ready to use carbs. Gels provide energy and often nutrients but without the water content. Depending on your course, available water and preference, you’ll have to plan what you take. Ensure you trial whatever you intend to use before event day. Warm, sickly sweet, sticky goos, can be a shock to the system if you’re not used to it. Other natural high GI foods can be suitable alternatives, such as fruit. There are sensible reasons why orange slices are given out at half time at football games. Some smaller races even have fruit plates and lollies such as snakes and jelly babies available at aid stations for those quick hits. You need to experiment to discover what works best for you.
Now we know how the body works during the event, let’s jump back to pre-event or pre-workout nutrition, to ensure your glycogen stores are full and you’re raring to go. We’ll assume that as someone who trains regularly that your day to day diet is of high quality and low in processed and sugary foods. The day before you will need to ensure you have stocked up (not excessively) on complex carbohydrates. Let’s explain what these are:-
Simple carbohydrates are foods that contain one or sometimes two different types of sugars and are processed very quickly by the body and used for energy. These foods are known to have a high glycaemic index (GI). If there is a physiological requirement for these foods, they will be quickly utilised as energy. If not, they can spike blood sugars causing insulin issues. Over the long term, constant nutritional abuse can cause conditions such as diabetes type II. It is during or directly following exercise that these foods can have their place.
Complex carbohydrates are foods that contain three or more sugars and are usually higher in fibre and contain a broader nutritional profile. These are the foods we need in the hours preceding workouts and races and take longer to process, releasing energy slowly. Examples of complex carbohydrates are potatoes, brown rice, oats, whole wheat foods. You may be able to see why those on strict paleo diets may struggle in endurance events without dietary adjustments. Carbs are not evil as the constant dieters would have you believe, they are just misunderstood. For more complex carb ideas, see: http://examples.yourdictionary.com/examples-of-carbohydrates.html
If you’ve had the appropriate amount of complex carbs the day before your event, then your glycogen stores will be maxed and out and you’re ready to roll. If you’re having a complete breakfast, it needs to be at least 2 hours before your event and you’ll need to eat between 200 to 400 calories of carb rich food. Be careful not to eat too much or you’ll be sluggish at the event. You don’t want your body concentrating on processing your breakfast whilst you’re trying to achieve your PR on a run. The closer to your event that you wake, the less food you should intake. A small breakfast can be taken over an hour out or a small piece of fruit 30 minutes from the start time. On event days, the trick is to take in appropriate nutrition when racing so early in the morning. Rising at 5 AM just to eat can be quite a chore and you may be trading food for sleep. Whatever time you rise before the event, just ensure that eating is your first job whether you’re hungry or not. And make sure you have planned and prepared the meal the day before. This meal can be as simple as a bagel with peanut butter, porridge and banana, breakfast shake or a muesli bar.
Directly after the workout or event, you will have a depleted glycogen store crying out for replenishment, this is where high glycaemic foods and drinks come into their own. At this time, your body is much more sensitive to carbohydrates and will be quick to store whatever you throw at it. The longer you leave it before you replenish, the window for appropriate recovery begins to close.
After your post-race hit and for the following few hours after the workout or event, your body is still craving nutrients. You should be switching back to meals with complex carbs and now start to include proteins for muscle repair. It helps to include foods with both protein and complex carbs such as; oats, brown rice, sweet potatoes, and legumes.
Now that you’ve conquered your event and you’re appropriately recovered, you can progress into the final stage of event nutrition, which is your daily, nutritious diet whilst remaining hydrated until your next event or training session.