Fuel Station

By Rachel Hannah Marathon Nutrition

You’ve just signed up for a marathon and can’t wait to start training. You’ve put a lot of thought into how to periodize your training so that you peak on the day of competition. But has the same level of detail and thought gone into your fuelling plan? Nutrition can have a huge impact on your performance, both during training and especially on race day. Your body stores carbohydrates in the form of glycogen in your muscles and liver, but in a limited supply. During endurance events of over 90 minutes we start to run out of these important energy reserves if we don’t take in carbohydrates while racing. (This, or insufficient training, is usually the reason first-time marathoners “hit the wall.”) Therefore, you should map out a plan well in advance to help you perform at your best.

Carb up

Carbohydrates include sugar, starch and fibre, and they’re found in plant-based foods (fruits, vegetables, grains and legumes) and dairy products. We need carbohydrates in the largest amount, since they are the main source of energy (glucose/glycogen) to fuel our activity. They also promote optimal brain and muscle function and help regular blood sugar levels.

Any time you will be training or racing for 90 minutes or more, you should be taking in carbohydrates, to help:

» maintain blood glucose concentration » maintain high rates of carbohydrate oxidation » reduce liver glycogen breakdown » reduce glycogen breakdown in the muscles during running » delay onset of fatigue » improve endurance capacity and performance

Athletes are at higher risk of developing Relative Energy Deficiency in Sport ( red- S) with endurance events and with an increase in mileage. Be sure to increase carbohydrate intake on workout and long-run days, when your body needs it most.

Sports Nutrition

Our bodies need sugar to keep going once our glycogen stores have been used up. Sports nutrition products like drinks, gels and chews are a convenient and portable way to obtain sugar during a long run or race, and at some races, gels are available at water st at ions. It ’s useful to experiment with different brands and products on your long runs to f ind out which f lavours and textures you enjoy and that your stomach tolerates well.

Note that our stomachs don’t cope well with high concentrations of sugar, which can cause gastrointestinal distress, but the gut is very adaptable/trainable. By consuming a high-carbohydrate diet and frequently using carbohydrates during sustained and hard efforts in training, you can train your gut to digest more while running. The amount of carbohydrate you should take per hour will vary depending on how fast you’re running. For most people, a good goal is to take on 45– 60 g per hour. Again, use your long runs to experiment with fuelling frequency. For runs of more than 90 minutes, start fuelling at about 45 minutes in, and plan to take in carbs and f luids every 5– 6 km.

Hydration

Fluid intake is individual and varies depending on many factors, including heat and humidity and your sweat rate. A general guideline is ½–1 cup every 15 to 20 minutes during exercise, but you should experiment in training to see what works well for you. It is highly recommended to use a sports drink, such as eLoad, Maurten, Skratch Labs, Tailwind or sos, that will replace electrolytes lost through sweating and to provide easily digested carbohydrates for training and racing.

For one-to-one support and a customized plan for race day, consider reaching out to a sports dietitian for help.

Rachel Hannah, RD, is a five-time Canadian champion, a Canadian Marathon Championships silver medallist and a Pan Am Games bronze medallist in the marathon. She is a full-time registered dietitian at the University of Guelph’s Health and Performance Centre and her own virtual private practice. She can be reached at rachelhannahrd@gmail.com.