Fuelling for Exercise – Tips from a Nutritionist

What is the best food to eat for exercise? How long before I exercise should I eat? What about refuelling after I exercise?

Training

If training for 1 hour or less, eat a small snack about 30 minutes before training. This could be a piece of toast, small banana, a few dates or a glass of fruit juice.

If training for longer than 1 hour, first thing in the morning, females should have a small snack of about 30g of carbohydrates. Males can train on empty. Our cortisol levels naturally are at their highest first thing in the morning (cortisol is our stress hormone). The best way for men to reduce their cortisol levels is by exercising and the best way for women to reduce cortisol levels is by having a small carbohydrate snack.

For training sessions longer than 1.5 hours, athletes should consume 30g of carbohydrates for each hour after the first hour. For example, if a training session lasts for 1.5-2 hours, eat 30g in the second hour. If your session lasts for three hours, eat another 30g in the third hour, and so on. These carbohydrates are easily and quickly broken down by our bodies into glycogen, which is the fuel our muscles use to move.

Fluids

As it is important to know what foods to eat, it is also vital to know how much water and electrolytes to drink. Dehydration can lead to increased body temperature and blood will move to your skin for cooling, leaving the muscles and brain short of blood flow. Dehydration during exercise can lead to loss of coordination, impaired ability to make a decision, increased rate of perceived exertion and increased risk of heat stress.

The body needs approximately 600ml – 1 litre of fluid for every hour of exercise, depending on your sweat rate, the weather (temperature and humidity), gender, body size, etc. This is on top of your normal daily water intake. Make sure that you drink at a rate that is comfortable for you.

Water is usually the best fluid for short periods of training and low intensity exercise. Sports drinks are suited to higher intensity “stop-go” type training and endurance sports.

It is also important to know how much fluid to drink during your training session, or race, as it can be dangerous to drink too much. Too much water during exercise is known as hyponatraemia (low levels of sodium in the blood). Symptoms include headaches, disorientations, and in rare cases, coma or death.

You find out how much to drink by calculating your sweat rate.

Calculating Your Sweat Rate

To calculate your sweat rate, weigh yourself (naked) pre and post a 1 hour run (at your approximate race pace) to see how much weight you have lost. A 1kg weight loss is equal to about 1 litre of fluid. You should aim to replace the up to amount lost, but never more than this amount (it can be dangerous to over-consume fluids). It is a good idea to test this seasonally as your sweat rate can vary depending on outside temperature.

Nutrition for Event Days

Whether you’re a sprinter, or a marathon runner, it is important to make sure you eat properly between or during your event/s. You can even devise a race plan.

For sprinters:

• Eat 1-3 hours before the race.
• Have a small snack 30 minutes before training eg piece of toast, banana, 2-3 dates, fruit juice (not drink)
• Make sure to rehydrate between races – small sips of water or sports drink are suitable (see fluids section above)
• Have a snack after each race, depending on the time in between races…
  • Less than 30 minutes – sip on a sports drink.
  • 1-2 hours – eat a small snack as soon as a race finishes to allow time to digest the food. Aim for 4 parts carbohydrates to 1 part protein. Examples are muesli bar or yogurt with fruit.
  • 2 or more hours – eat a small meal within the first hour with 3 parts carbohydrates to 1 part protein. Examples are sandwich, white rice with protein, smoothie, etc.

For marathon runners:

What’s the deal with carbohydrate loading? This is done to ensure adequate levels of glycogen in the body for race day. So, how do you do it?

• For the week before the race, aim to increase your carbohydrate intake slowly. For 7,6 and 5 days before the race, aim for carbohydrate intake to be 50% of your diet.
• For days 3, 2 and 1 before the race, increase carbs to 70% of your food intake. Make sure to reduce protein and fat levels at this time too to avoid over-eating.
• This is also a good time to reduce fibre intake to limit the chance of gastrointestinal upset during the race. Aim for white rice and pasta instead of wholegrains for the last day or two before the race.

On race day:

• Aim to eat 2-3 hours before the race start (but don’t sacrifice sleep for food).
  • Aim for 1-2g of carbohydrates per kilo of body weight (eg a person who weighs 70kg should aim for 70-140g of carbohydrates, eating the smaller end of the scale the closer you are to race start time.
  • Make sure the meal is low in fibre, protein and fat to reduce chances of stomach problems during the race.
  • Options include white bread, crumpets, jam, honey, bananas, smoothies.
• Consume fluids during the race according to your sweat rate and drink at a rate that you are comfortable with. Practice this during your training sessions.
• Consume 30-60g of carbohydrates per hour during a race. This amount will reduce fatigue and will be absorbed quickly. See the table below for examples of 30g of carbohydrates in food. Many people choose to use sports gels during races. These usually contain 20-30g of carbohydrates per packet (refer to the package label).

Post-Training/Event Nutrition

This is the most important time to eat! Not eating after exercise can hinder replacement of glycogen (we want glycogen to be replaced quickly so we are ready for the next session) and compromise your immune system. Aim to eat within 30-45 minutes of finishing training, at a ratio of 3-4 parts carbohydrates to 1 part protein. This ratio is best for muscle recovery and will help to replace glycogen stores for the next training session. Aim for approximately 30-80g carbohydrates and 10-20g protein, depending on whether you are having a meal or a snack. Examples include a muesli bar (check the label), yogurt with fruit, smoothie, rolled oats with fruit and a boiled egg, or eggs on toast.

Carbohydrates to choose from include fruit, vegetables, bread, rice, pasta, oats, cereals and other grains. Protein choices include meat, fish, chicken, eggs, dairy, nuts & seeds, beans and protein powders.

What does 30g of carbohydrates look like?

How much protein is in food?

What Not to Do…

• Don’t consume food or gels with a sports drink. If there are too many carbs in the stomach (more than 8%), gastric emptying can be delayed and gastrointestinal problems start such as pain, nausea, constipation and/or diarrhoea. Sports drinks are already 5-8% carbs – having anything else will take you over 8%.
• Don’t drink alcohol to replenish carbs. Alcohol inhibits our body’s ability to make more glycogen and slows healing of muscle tissue.
• Don’t eat fatty foods such as hot chip, sausage roll, meat pies during event days (if at all). They are high in fat and will take too long to digest.
• Never try anything new on event days!

Remember: Use your training sessions to practice these nutritional tips, just as you would practice tips from a running coach.

What else can you do?

Follow these tips to improve your recovery, as well as performance during training and events. You will feel great after training and should see an improvement in your performance.

See a nutritionist or naturopath with an interest in sports nutrition to help you devise a race plan, if you have special dietary recommendations, or are not seeing results on your own.