THE TRAINING DIET Recommendations for athletes¹ intakes of energy, macronutrients, vitamins, and minerals are described elsewhere in this document. These recommendations are often presented in terms of milligram or gram amounts of nutrients (eg, 6 to 10 g carbohydrate/kg body weight) and must be translated into food choices consistent with food preferences and training schedules of athletes (109). The foundations (proportion of energy from protein, fat, and carbohydrate) for the training diets of athletes, however, do not differ substantively from current recommendations for the general population. Thus, the training diet should incorporate the principles outlined in the Dietary Guidelines for Americans (50) and Canada¹s Guidelines for Healthy Eating (110), and be based on the 1992 US food guide (US Food Guide Pyramid) (111) or the 1992 Canadian food guide (Canada¹s Food Guide to Healthy Eating [112]). The fundamental differences between an athlete¹s diet and that of the general population are that athletes require additional fluid to cover sweat losses and additional energy to fuel physical activity. As discussed earlier, it is appropriate for much of the additional energy to be supplied as carbohydrate. Though in some cases needs for other nutrients also increase (eg, protein, B-complex vitamins), the proportional increase in energy requirements appear to exceed the proportional increase in needs for other nutrients. Accordingly, as energy requirements increase, athletes should first aim to consume the maximum number of servings specified in both food guides from carbohydrate-based food groups (breads, cereals and grains, vegetables, and fruits). For many athletes, however, energy needs will exceed the amount of energy (kcals per day) in the upper range of servings for these food groups as provided by both food guides. To maintain dietary variety, these athletes may also increase the number and/or size of servings of dairy products and protein foods, but should aim to keep the proportions of energy provided by different food groups consistent with those identified in both food guides. Conversely, athletes who are small and/or have lower energy needs will need to pay greater attention to making nutrient-dense food choices to obtain adequate carbohydrate, protein, and micronutrients. The other issue that arises in a discussion of the diet of athletes relates to the timing of meals and snacks. Common sense dictates that food and fluid intake around workouts needs to be determined on an individual basis and will depend, in part, on an athlete¹s gastrointestinal characteristics as well as the intensity of the workout. For example, an athlete might tolerate a snack consisting of milk and a sandwich 1 hour before a low-intensity workout, but would be uncomfortable if the same meal was consumed before a very hard effort. In any case, athletes in heavy training or doing multiple daily workouts may need to eat more than 3 meals and 3 snacks per day and should consider every possible eating occasion (113). For example, they should consider eating in close proximity to the end of a workout, having more than one afternoon snack, or eating a substantial snack before bed. Preexercise Meal Eating before exercise, as opposed to exercising in the fasting state, has been shown to improve performance (114-116). The meal or snack consumed before competition or an intense workout should prepare athletes for the upcoming activity, and leave him or her neither hungry nor with undigested food in the stomach. Accordingly, the following general guidelines for meals and snacks should be used: sufficient in fluid to maintain hydration, low in fat and fiber to facilitate gastric emptying and minimize gastrointestinal distress, high in carbohydrate to maintain blood glucose and maximize glycogen stores, moderate in protein, and composed of foods familiar to the athlete. The size and timing of the preexercise meal are interrelated. Because most athletes do not like to compete on a full stomach, smaller meals should be consumed in closer proximity to the event to allow for gastric emptying, whereas larger meals can be consumed if more time is available before exercise or competition. Amounts of carbohydrate used in studies in which performance was enhanced have ranged from approximately 200 to 300 g carbohydrate for meals consumed 3 to 4 hours before exercise (114-117). The recommendations on carbohydrate consumption within 1 hour before activity have been controversial. Early research suggested that this practice leads to hypoglycemia and premature fatigue (118); however, more recent studies report either no effect or beneficial effects of pre-event feeding on performance (53,114,119-121). Current data are mixed concerning whether the glycemic index of carbohydrate in the preexercise meal affects performance (122,123). Although the above guidelines are sound and work well on average, the individual needs of the athlete must be emphasized. For example, some athletes consume and enjoy a substantial meal (eg, pancakes, juice, and scrambled eggs) 2 to 4 hours before exercise or competition; however, others may suffer severe gastrointestinal distress following such a meal and need to rely on liquid meals. Athletes should always ensure that they know what works best for themselves by experimenting with new foods and beverages during practice sessions and planning ahead to ensure they will have access to these foods at the appropriate time. CARBOHYDRATES: How Much?; Nutrition and Performance:PART 1; Nutrition For Active Adults PART 2, Energy Needs: PART 3, Body Composition: PART 4, Carbs, Fat, Protein, REFERENCES © ADAF 1999. Reproduction of this fact sheet is permitted for educational purposes.