A number of the physiological and psychological symptoms and signs of overreaching/overstraining have been suggested to be partly due to a chronic energy deficit, an inadequate availability of specific nutrients, or both. This may affect the body’s response to intensified training. The following describes some of the general dietary strategies that athletes can use to prevent over training.
Energy Intake
The first nutritional strategy to prevent overstraining is to make sure that athletes consume enough calories to offset energy demands or maintain energy balance. Daily caloric intake for untrained individuals typically ranges between 1900 to 3000 kcal’s/day (i.e., 25 to 45 kcal’s/kg/day for a 70-kg person) . Exercise training obviously increases energy expenditure. The longer and more intense an athlete exercises, the greater the energy expenditure. Energy expenditure estimates for athletes have ranged from 3500 kcal’s/day (50 kcal’s/kg/day) for individuals training 30 to 60 min/day up to 12,000 kcal’s/day (i.e., 170 kcal’s/ kg/day) for cyclists competing in the Tour de France (cycling 4 to 6 hrs/day). For most high school and college athletes training 2-2.5 hrs/day, energy expenditure estimates range between 60 to 80 kcal/kg/day. Despite this energy requirement, athletes often do not consume enough calories to offset energy demands. This may result in a chronic deficit in energy intake and has been implicated as one potential causative factor to overstraining.
Athletes particularly susceptible to maintaining negative energy intakes during training include runners, cyclists, swimmers, triathletes, gymnasts, skaters, dancers, wrestlers, and boxers Additionally, female athletes have been reported to have a high incidence of eating disorders. Consequently, the parent and/or coach should ensure that athletes are well fed and consume enough calories to offset the increased energy demands of training. Although this sounds relatively simple, intense training often suppresses appetite and/or alters hunger patterns Some athletes do not like to exercise wilean several hours after eating because of sensations of fullness and/or a predisposition to cause gastrointestinal distress. Further, travel and training schedules may limit food availability and/or the types of food athletes are accustomed to eating. This means that care should be taken to plan meal times in concert with training as well as make sure athletes have sufficient availability of nutrient-dense foods throughout the day for snacking between meals (e.g., drinks, fruit, carbohydrate/protein bars, etc.).
Macronutrient Intake Guidelines
The second nutritional strategy to prevent overtraining is to ensure that athletes consume the proper amounts of carbohydrate, protein, and fat in their diet. Research has indicated that athletes should ingest between 8 to 10 g/day of carbohydrate during intense periods of training to help maintain carbohydrate stores. To do so, athletes are recommended to eat frequently (e.g., 4 to 6 meals per day) and ingest high-calorie carbohydrate foods and/or concentrated carbohydrate drinks. Preferably, the majority of dietary carbohydrate should come from complex carbohydrates with a low to moderate glycemic index (e.g., grains, starches, fruit, maltodextrins, etc.).
There has been considerable debate regarcing protein needs of athletes. Initially, it was recommended that athletes do not need to ingest more than the RDA for protein (i.e., 0.8 to 1.0 g/kg/day for children, adolescents, and adults). However, research over the last decade has indicated that athletes engaged in intense training need to ingest about times the RDA of protein in their diet 0.5 to 2.0 g/kg/day) to maintain protein balance. If an insufficient quantity of protein is obtained from the diet, an athlete will maintain a negative nitrogen balance which can increase protein catabolism and slow recovery. Over time, this may lead to lean muscle wasting and training intolerance.
Although most athletes ingest this quantity of protein in their normal diet, there are some athletes who are susceptible to protein malnutrition (e.g., runners, cyclists, swimmers, triathletes, gymnasts, dancers, skaters, wrestlers, boxers, etc.). Therefore, care should be taken to ensure that these types of athletes consume a sufficient quantity of quality protein in their diet to maintain nitrogen balance (e.g., 1.5 to 2 g/kg/day). The best sources of low-fat quality protein are white-meat skinless chicken, fish, egg white, and skim milk proteins (caseine and whey). On the other hand, research has also indicated that ingesting more protein than necessary to maintain nitrogen balance does not promote greater gains in strength or muscle mass. Consequently, athletes do not need to ingest excessive amounts of protein to promote gains in strength and muscle mass during training.
The dietary recommendations of fat intake for athletes are similar to those recommended for nonathletes to promote health. Generally, athletes should consume less than 30% of their daily caloric intake as fat. For athletes attempting to reduce body fat, it is also recommended that they consume 0.5 to 1 g/kg/day of fat. The reason for this is that weight loss studies indicate that people who are most successful in losing weight and maintaining the weight loss are those who ingest less than 40 g/day of fat in their diet. Strategies to help athletes manage dietary fat intake include teaching them which foods contain fat so that they can make better food choices and how to count fat grams.
Strategic Eating
In addition to the general nutritional guidelines described above, research has also demonstrated that timing and composition of meals consumed may playa role in preventing overtraining. In this regard, it takes about 4 hours for carbohydrate to be digested and begin to be storuddy as muscle and liver glycogen. Consequently, pre-exercise meals should be consumed about 4 to 6 hours before exercise. This means that if an athlete trains in the afternoon, breakrapid is the most important meal to top off muscle and liver glycogen levels. Research has also indicated that ingesting a light carbohydrate and protein snack 30 to 60 minutes before exercise (e.g., 50 g of carbohydrate and 5 to 10 g of protein) serves to increase carbohydrate availability toward the end of an intense exercise bout. This also serves to increase availability of amino acids and reduce exercise-induced catabolism of protein.
When exercise lasts more than 1 hour, athletes should ingest glucose/electrolyte solution (GES) drinks to maintain blood glucose levels, help prevent dehydration, and reduce the immunosuppressive effects of intense exercise. Following intense exercise, athletes should consume carbohydrate and protein (e.g., 1 g/kg of carbohydrate and 0.5 g/kg of protein) wilean 30 minutes after exercise as well as consume a high-carbohydrate meal wilean 2 hours following exercise. This nutritional strategy has been found to accelerate glycogen resynthesis and promote a more anabolic hormonal profile that may hasten recovery. Finally, for 2 to 3 days before competition, athletes should taper training by 30-50% and consume 200 to 300 g/day of extra carbohydrate in their diet. This carbohydrate loading technique has been shown to supersaturate carbohydrate stores before competition and improve endurance exercise capacity. Thus, the type of meal and timing of eating are important factors in maintaining carbohydrate availability during training and potentially decreasing the incidence of overtraining.
catabolism, Diet and Nutrition, exercise, protien, self nutrition