Feeding Your Workout Success
By Andrea Chernus
One of the hottest topics in sports nutrition is nutrient timing: what to eat before, during and after exercise. The goal is to provide enough fuel to working muscles when needed without sacrificing performance. Consuming food or fluids after training maximizes muscle repair, restocks used energy and helps to prepare athletes for their next session. In order for nutrient timing to be truly beneficial, athletes need to consume a balanced diet of sufficient calories from carbohydrates, proteins and fat through the entire day.
The type of pre-workout snack will vary based on timing and the type of training. For endurance sports such as running, cycling, distance swimming, hiking and cross-country skiing, we don’t want food to stay in the stomach too long and cause discomfort. Basically, the closer to training, the smaller and purer the needed carbohydrate; it must be easy to digest with very little fibre. Most athletes can tolerate 15 grams of quick-digesting carbs immediately before exercise. Thirty minutes ahead, 25 grams of carbohydrate is fine, while eating up to 400 calories of mostly carbohydrate with a little protein for staying power is recommended if you can plan forward a couple hours.
When there is more time, having a meal up to four hours prior gives the body time to digest, absorb and store nutrients as glycogen in muscles. While a small amount of fibre and protein are OK, avoid very spicy foods or extraordinarily high-fat items.
A snack just before taking to the road, pool or hills will top off your storage tank and prevent using up glycogen too quickly. For training first thing in the morning, a small snack of at least 15 grams of carbohydrate is recommended to counter the low levels of blood sugar and stores of glycogen in the liver. A 2008 study suggested that carbohydrates eaten 15 minutes before morning exercise allowed athletes to run 12.8 per cent longer than those who hadn’t eaten.
Protein is a concern for those doing resistance training. Some athletes believe protein before taking to the gym is a must, while others eat nothing. Who is right? Studies have found when amino acids, the building blocks of protein, are consumed before resistance training, they have more impact on muscle building than if eaten after a workout. Muscle building performance was the same before and after the workout when the protein was a whole food, specifically whey protein derived from milk. We don’t know if eating a complete meal prior to training would alter these results. More research is needed to determine if consuming protein before resistance training is necessary or more effective than at any other time.
Just as with endurance training, a small snack before early-morning workouts is in order. This should be focused on carbohydrates, the fuel muscles burn to lift weight. A small amount of protein can be added if desired, up to 20 grams.
It’s important to take in fuel during any training that lasts longer than 60 minutes and is essential for exercise over 90 minutes. Since fluid is also needed, many athletes find it easy to fuel and hydrate with a sports drink. Fruit juices often cause stomach upset if consumed during endurance training because their high sugar content is hard for the body to absorb rapidly. A beverage with six to eight per cent carbohydrate is tolerated well, meaning one with 14 to 20 grams of carbohydrate per 250 ml and at least 80 mg sodium. Many athletes can comfortably consume 30 to 60 grams of carbohydrate per hour during endurance work, some even more. One reason sports drinks work well is because they have a mixture of sugars that are absorbed more quickly than beverages with only one type of sugar. Sodium helps replace some of what is lost in sweat. It also helps to retain and distribute fluids where they are needed in the body. Drinking or eating small amounts during a training session or event improves absorption. Having some food or fluid in the stomach actually helps the stomach to empty more quickly than if the stomach is empty. Taking food or fluid every 10 to 15 minutes is a strategy that works well for many athletes. For example, if 30 grams of carbohydrate was the desired intake, one might take 125 ml of a sport drink every 15 minutes. Some athletes prefer energy gels, the concentrated carbohydrates with a pudding-like consistency, which each provide about 25 to 30 grams of carbohydrate. If using gels, be sure to drink enough water to meet fluid needs.
Sports drinks are effective during resistance training because carbohydrates fuel muscle contraction. Carbs taken during training can spare muscle glycogen from being depleted, which may lead to excess muscle soreness.
Eating soon after training is most important when athletes train long or hard. For two-a-day training sessions or competitions, it’s important to begin recovery as soon as possible because of the limited time to restore and replenish. For athletes training at a moderate to high intensity on a daily basis, recovery should begin within 30 minutes if possible and definitely within two hours. In the first two hours after a workout, enzymes that store carbohydrate are at their peak and the rate of glycogen storage is fastest. As time goes on, storage continues at a slower rate. It can take up to 20 hours to fully restore depleted supplies of glycogen.
Timing is not as crucial for recreational athletes or gym-goers training moderately three to four times a week, these athletes can replace used fuel well before their next session. Nutritional recovery should still begin as soon as possible, but all is not lost if nothing is consumed in 15 or 20 minutes. Still, the sooner the process begins, the better. Best recovery snacks include a good source of quickly digested carbohydrate and a small amount of protein. Depending on the intensity and duration of training, 1 to 1.5 grams per kg body weight should make up the carbohydrate, while 10 to 20 grams of protein will aid in muscle repair. In two hours, the snack may be repeated, or a meal taken.
It’s best to repeat meals and snacks throughout the remainder of the day. Smaller servings of protein are utilized more efficiently than one large amount.
Be sure to eat at regular intervals to supply sufficient protein, carbohydrate and calories to repair and replenish working muscles.
Andrea Chernus is a registered dietician and co-author of Nutrient Timing For Peak Performance (Human Kinetics 2010).