How often have you had a bite from an energy bar, taken a sip from an energy drink, or eaten a meal an hour or less before a race or long training session? Big mistake! Eating this soon before prolonged exercise is actually counterproductive and will hurt your performance.
You need to know what to eat, how much and when. You also need to know a bit about glycogen storage, depletion, and resupply, and how to use apply this knowledge to your lifestyle.
The goal of pre-exercise calorie consumption
Assuming that your workout or race starts in the morning, the purpose of your pre-race meal is to top off liver glycogen stores, which your body has expended during your night of sleep. Muscle glycogen, the first fuel recruited when exercise commences, remains intact overnight.
You might wake up feeling hungry, but you’ll have a full supply of muscle-stored glycogen. Your stomach might be saying, “I’m hungry,” but your muscles are saying, “Hey, we’re good to go!”
You want a light pre-race meal. It is advised that a pre-workout/race meal should be easily digested, high in complex carbohydrate, with a minimum of fibre, simple sugar and fat. You don’t want an unscheduled bathroom break in the middle of the event.
Complex carbohydrates and protein
One study found that athletes who drank a meal consisting of both carbohydrates and a small amount of protein had better performances than when they consumed only an all-carbohydrate sports drink.
If you do feel the need for solid food, choose high starch foods such as skinless potatoes, bananas, rice, pasta, low fat active culture yogurt and low fibre hot cereals.
The key – Allow three hours or more!
Authorities agree that the pre-race meal should be eaten 3-4 hours prior to the event. Three hours allows enough time for your body to fully process the meal and avoid intestinal distress.
It’s all in the timing
If you consume high glycaemic or complex carbohydrates within three hours of exercise, you can expect the following:
• Rapidly elevated blood sugar causes excess insulin release, leading to hypoglycaemia, an abnormally low level of glucose in the blood.
• High insulin levels inhibit lipid mobilisation during aerobic exercise, which means reduced fats-to-fuels conversion.
• A high insulin level will induce blood sugar into muscle cells, which increases the rate of carbohydrate metabolism. In simple terms: high insulin means faster muscle glycogen depletion.
You must complete your pre-workout/race fuelling three or more hours prior to the start to allow adequate time for insulin and blood glucose to normalise, restore hormonal balance and reduce your risk for increased glycogen depletion. The combination of accelerated glycogen depletion and disruption of your primary long-distance fuel availability can devastate your performance.
Are there any exceptions to the three-hour rule?
When you’re engaged in training sessions or races in the 90-minute range or shorter, fasting three hours prior to the start is not necessary. Consuming some easily digested calories an hour or two prior to the start will not negatively affect performance, and may actually enhance it.
When you consume calories sooner than three hours prior to the start of a workout or race, you accelerate the rate at which your body burns its finite amounts of muscle glycogen stores.
In events lasting longer than 60-90 minutes, refraining from calorie consumption for the three-hour period prior to the start is crucial because you want to preserve your glycogen stores, not accelerate their depletion.
Article supplied by On Running