Some of the questions most frequently asked of sports dietitians deal with food and fluid consumption before, during and after exercise. Indeed, athletes are bombarded with nutrition misinformation, resulting in confusion about what they should eat or drink during training or, more crucially, during competition. This article provides science-based guidelines on food and beverage choices that are easy to understand and adopt and that allow athletes to maximize their potential.
Recently, the American Dietetic Association, Dietitians of Canada and the American College of Sports Medicine published a joint position statement regarding nutrition and athletic performance (Rodriguez et al. 2009). Among other topics, the position statement used evidence-based science to make recommendations for athletes on food and fluid consumption before, during and after activity. Using this document as a foundation, the guidelines described here have been developed to provide practical recommendations that sports dietitians can use to help athletes make food and fluid choices before, during and after workouts or competition.
1. Athletes should eat before physical activity as opposed to working out in a fasted state (Rodriguez et al. 2009).
Consuming foods high in carbohydrates (CHO) before exercise increases muscle glycogen stores and maintains blood glucose. Studies have shown that consuming a pre-exercise meal low in fiber and fat, moderate in protein and high in CHO can extend the exercise time and provide added energy (Jentjens et al. 2003; Moseley, Lancaster & Jeukendrup 2003).
2. At least 4 hours before activity, athletes should drink about 5–7 milliliters [ml] per kilogram of body weight (2–3 ml per pound of body weight) of water or sports drink (Rodriguez et al. 2009).
Consuming fluids at least 4 hours prior to a workout allows enough time to optimize hydration status and allow for excretion of excess fluid (Rodriguez et al. 2009). Fluid consumption will vary
depending on environmental factors,
exercise intensity, body size, training status and gender. A sports drink consumed before exercise should contain 6%–8% CHO (60–80 grams CHO per liter) and 110–165 milligrams of sodium per 8-ounce (oz) serving (Chryssanthopoulos & Williams 1997; Chryssanthopoulos et al. 2002).
3. The volume of the preworkout meal or snack, the timing of ingestion and the start of the workout are all interrelated (Rodriguez et al. 2009).
Athletes should consume smaller meals closer to the start of a competition, while larger meals should be consumed further out from the workout. Studies on CHO in which athletes consume 200–300 g of CHO 3–4 hours before competition have shown that this helps performance (Rodriguez et al. 2009; Bloch & Wheeler 1999). Athletes may benefit from consuming liquid CHO, such as pre-exercise beverages or gels (25 g CHO/4 oz) or sports drink (containing 6%–8% CHO solution) an hour or less before the start of activity (Anantaraman et al. 1995). Consuming a concentrated source of CHO around 15 minutes before a workout works well when athletes do this in conjunction with CHO intake during that workout.
4. Athletes’ individual needs and preferences should be identified and met (Rodriguez et al. 2009).
Athletes should always experiment with the type, amount and timing of a preworkout meal before a training session; they should not start a new strategy at the time of a competition. This will allow athletes to find meals that work for their events and not interfere with performance.
Nutrition During a Workout
1. Research supports the benefit that CHO consumption in amounts typically provided in sports drinks (6%–8% CHO) has on endurance performance in events lasting 1 hour or less (Rodriguez et al. 2009; Sugiura & Kobayashi 1998; Jeukendrup et al. 1997; Nicholas et al. 1995).
2. For longer events, consuming 30–60 g CHO/hour has been shown to extend endurance performance (Rodriguez et al. 2009).
This is especially important for athletes who have not consumed a preworkout meal or have restricted calories or CHO during exercise, for maintenance of blood glucose.
3. Consumption of 6–12 oz of sports drink with 6%–8% CHO every 15–30 minutes during a workout can extend the workout capacity of athletes who participate in intermittent activity (Jeukendrup et al. 1997; Anantaraman et al. 1995; Below et al. 1995; Carter et al. 2003; el-Sayed, Balmer & Rattu 1997).
Nutrition for Postworkout and Recovery
1. It is important to replace fluids and electrolytes that are lost during activity. Consuming rehydration beverages and salty foods during meals/snacks will help replace fluids and electrolyte losses (Rodriguez et al. 2009).
Athletes should drink 16–24 oz of fluid for every pound of body weight lost (and not replaced) during activity (Rodriguez et al. 2009). It should be recognized that complete rehydration requires sufficient sodium and potassium replacement and extra fluid intake exceeding that which is lost in sweat and urine during activity.
2. Timing and composition of the
postexercise meal depends on the intensity and duration of the exercise session and when the next workout will occur (Rodriguez et al. 2009).
Not all athletes need to practice recovery nutrition. For example, a cross-country runner who trains in easy runs before a tapering week does not empty glycogen stores and has enough time for complete recovery before competition. For those doing intense training multiple times a day, an appropriate diet strategy between workouts will be very relevant and important.
3. Timing of postworkout CHO intake affects glycogen synthesis.
Consumption of 1.0–1.5 g of CHO/kg within 30 minutes after exercise and at 2-hour
intervals (up to 6 hours) results in higher glycogen levels than when ingestion is
delayed for 2 hours (Rodriguez et al. 2009).
When the recovery period is limited to only a few hours, rehydration and refueling can be achieved by ingesting a CHO-electrolyte solution in volumes of at least 150% of the workout-induced loss in body weight and by consuming CHO-rich foods (Moore et al. 2009).
4. Protein plays a role in recovery nutrition.
The joint position statement addressed the fact that adding protein to a recovery regimen does not increase muscle glycogen to a greater extent than CHO alone when CHO is consumed in recommended amounts (Rodriguez et al. 2009). However, adding protein to the recovery snack will provide amino acids for building, maintenance and repair of muscle.
While CHO is the primary source of energy for muscles, consuming a small amount of protein shortly after activity assists in the repair and synthesis of muscle protein in the body. Athletes should meet their protein requirements by consuming protein throughout the day rather than ingesting it all in one meal or snack. Research by Howarth et al. (2009) suggests that about 20 g of protein is the maximum amount needed to stimulate synthesis and repair of muscle.
In addition, research shows that ingestion of 7–10 g of protein along with CHO within 30 minutes of physical activity is enough to start muscle protein synthesis. Repeated feedings up to 6 hours postworkout may help provide a pulsing effect for muscle rebuilding over time (Moore et al. 2009).
Optimal Nutrition Toward Optimal Performance
Adopting nutrition strategies presented within the joint position statement can improve physical activity tolerance and help athletes recover rapidly from training and competition. An important premise of these general recommendations is that the optimal mixture of nutrients to speed recovery from hard training and competition can be obtained by eating wholesome foods and beverages, provided correct choices are made regarding food type, amount and timing.
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