Performance Boosters

Eating the right kinds of food boosts performance, athletic or otherwise. Combine good nutrition with proper training, adequate rest and recovery, and you'll have the key to success. There are several nutrients in the diet that are essential in keeping your performance at its best, namely, carbohydrates, protein, vitamins, minerals and water.

Carbohydrates

Carbohydrates are the body's main source of energy during exercise. The carbohydrates in foods break down into glucose (sugar) in the body. This sugar is then either used immediately as energy or is stored in the muscle and liver as glycogen for later use. Once glycogen stores are used up, the athlete experiences decreased endurance, followed by fatigue and exhaustion. Carbohydrate foods are then needed to replenish glycogen stores.

Making the Choice - Complex or Simple Carbohydrates

"Complex" carbohydrates are the best choice for strength and endurance as they contain more vitamins, minerals and fibre than their "simple" counterparts. Think of complex carbohydrates as "slow release" energy, the kind that is even and long lasting, whereas simple carbohydrates give quick bursts of energy but don't last long.

According to the Sport Medicine & Science Council of Canada, athletes in most sports need at least 8 servings of Grain Products and at least 8 servings of Vegetables and Fruits each day to meet energy needs and maintain energy levels. If your training includes more than one hour per day of activity it is important to eat enough carbohydrate foods. Do this by ensuring that at least 50% of your total daily calories come from carbohydrates.

The "Carbo Load"

"Carbo loading" works well for endurance activities. The idea is to load up on carbohydrates a few days prior to competition to give glycogen stores the chance to fill up. Many endurance athletes "carbo load" all throughout their training as their bodies require the added carbohydrates to meet their high energy demands. "Carbo loading" is then combined with tapering off of activity a few days prior to the event to maximize the energy you will have for the event. "Carbo loading" meals contain 65-70% carbohydrate by calories.

Pre-exercise meal

It is best to eat 2-3 hours before competing to allow the food to be absorbed. The meal should be made up of mostly carbohydrate foods. Since protein and fat take longer to digest, carbohydrates will provide the usable energy that is needed. Drink fluids with the pre-exercise meal to ensure adequate hydration going into the event. Now is no time to experiment with anything new! Eat something you are familiar with as any changes in your diet may lead to an upset stomach. Good examples of pre-exercise meals include:

• Pasta and tomato sauce with vegetables
• Whole grain cereals with cow's milk or soy milk, fresh fruit and whole grain toast
• Plain or fruit flavored yogurt, muffin and fruit
• Sandwiches made with lean meat, chicken or fish

If time doesn't allow for a meal, choose a snack-sized portion of your favorite pre-exercise meal.

During exercise

Thirty to 60 grams of carbohydrate every hour after the first hour of exercise helps to maintain energy. For example 500ml of Gatorade supplies 30 grams of carbohydrate. For activities lasting longer than one hour, sports gels and energy bars are other ways of keeping your energy up. If you decide to use sports gels or bars to supply carbohydrate and salts, make sure to drink water with them. As there are many sport beverages, bars and gels on the market, talk to a Registered Dietitian to find out which ones, if any, are right for you.

After exercise

It can take up to 48 hours to replenish glycogen stores. Within the first 15 minutes after exercise start reloading glycogen stores. Continue to eat small frequent snacks in the hours following exercise. Research shows that combining carbohydrate and protein foods after intense exercise may be more effective than carbohydrate alone. Choosing yogurt and fruit, a meat sandwich or your favorite high carbohydrate energy bar should do the trick!

The Importance of Hydration

During exercise, working muscles cause the body's temperature to increase. Sweat, which is made up of water and salt, evaporates from the skin to keep the body cool, thus playing an essential role in regulating body temperature. Drinking enough of the right kinds of fluids in order to keep adequately hydrated allows your body to replace the water and salt lost during sweating and keeps fatigue, cramps and heat exhaustion at bay.

General tips to keep you hydrated:

• Don't rely on your thirst to tell you whether or not you are drinking enough. If you are thirsty it's already too late
• Drink enough fluid each day to keep your urine colorless and odorless. For most of us that means 8-10 cups or 2-2 1/4litres of fluid each day

Exercise-specific tips:

• Drink 500ml (2cups) of water 2 hours before doing any exercise
• Additional water can be sipped before exercising begins
• Drink 150 - 350ml every 15-20 minutes during exercise. Plain water is enough if exercise lasts less than one hour
• If exercising longer than one hour include a carbohydrate and salt source (fruit juice, sports drinks, such as PowerAde or Gatorade)
• Having 30-60g of carbohydrate every hour after the first hour of exercise (e.g. 500ml of Gatorade supplies 30g of carbohydrate) helps to maintain energy.
• Beware of some drinks, especially if you mix them yourself (e.g. PowerAde or Gatorade powder) if mixed incorrectly they can cause cramps and diarrhea as they provide too much simple sugar during exercise
• After exercise drink enough fluids to regain weight lost during exercise. During exercise 1kg weight loss = 1L of water loss

Best bets for hydration:

• Water
• Juice
• Milk
• Soup
• Sports drinks
• Caffeine free (or decaffeinated) beverages

For more information on hydration read Drink Up!

Protein

• Despite popular belief, additional protein in the diet does not stimulate muscle growth - exercise does!The average person requires 0.86 grams of protein per kilogram of body weight per day
• Endurance athletes require more for muscle repair, approximately 1.2-1.4g/kg/d. To include a margin for strength activities, protein requirement increases slightly to 1.4-1.6g/kg/d.
• The increase in protein requirement is almost always met by the increase in calories required to keep up with your hunger - protein supplements are not generally recommended for most people. Protein intake above your requirement puts strain on your liver and kidneys. Eating 3-4 ounces of high quality proteins 3 times daily (the upper recommended range of servings as outlined in Canada's Food Guide to Healthy Eating) will meet these needs of most people. If in doubt, talk to you doctor or Registered Dietitian
• Choose high quality, lean protein e.g. meat, fish, poultry, eggs, and soy. Other protein sources such as legumes, dairy and whole grains (whole wheat breads and pastas, brown rice) contribute protein as well
• Protein can contribute up to 5-10 percent of energy during endurance activity after glycogen stores are depleted

Vitamins and Minerals

Although vitamins and minerals do not provide energy they help our bodies to use the energy from food.

• Peak performance requires adequate iron intake. The Ministry of Health has excellent resources called Iron and You and Iron Content of Common Food. Visit BC Health Files to view the handout or print off a copy
• Vitamin E and Calcium are essential too.
• Although it is always recommended to obtain the needed vitamins and minerals from foods first, a broad-spectrum daily multivitamin and mineral supplement can help to cover your bases. The riboflavin in a multivitamin has a bright yellow water-soluble harmless pigment that will color your urine. If you are taking a multivitamin with a large amount of riboflavin it will make it more difficult to tell if you are adequately hydrated.

For more information on the subject read Nancy Clarks' Sports Nutrition Guidebook. Just getting started? Local recreation centres and many running shoe stores have clinics to help you get started and keep you on track. Eat well and have fun!