Monday, April 25, 2011

Young Players Diets are Left Wanting

The energy demands of training and match play can be tremendous. Running, sprinting, cutting, turning, and jumping all add to the energy cost of soccer. In fact, studies show that a soccer match requires more total energy than almost any other sport. At the Science of Soccer Online, we have stressed the need for players to eat a solid diet. Years of research has shown that a diet high in carbohydrates and low in fat is the best way to maintain energy stores and insure peak performance throughout the match. Replenishing lost muscle glycogen is essential to training and competing day after day. However, do players heed this advice? Do they eat the proper diet? A study headed by Mark Russell and Anthony Pennock of Moulton College and Swansea City Association FC asked young professional players these questions. The examined their diets and found that they lacked in total calories and contained too much fat and too few carbohydrates.

The researchers focused on ten male players (17 years old) that played for a Championship soccer team in the United Kingdom. During the month of October, in the initial part of the competitive season, players completed diet sheets on which they recorded all of the foods that they ate. The records included foods eaten, serving sizes, cooking methods and times eaten. They players also recorded beverages that they drank as well as any supplements that were taken. All were thoroughly instructed on how to accurately record all of this information. The food records were then carefully examined by the researchers and each player attended an interview session to clear up any ambiguous information. The diet records were then analyzed to determine the number of calories eaten as well as the specific components of each player’s diet.

Energy expended during the same period was estimated from laboratory measurements of their basal metabolic rate and on the specific durations and intensities of each match or training session.

The players consumed a total of 2,831 calories per day. This translates to 42.3 calories per kg of body weight per day (19.0 calories per lb of body weight). However, energy expenditure was estimated at 3,618 calories per day. That results in an energy deficit of 788 calories each day. That is, the players ate nearly 800 calories less than they used.

The researchers also found that the player’s diets were composed of 56% carbohydrates, 16% protein and 31% fat. As for recommended intake, these diets are somewhat high in fat and low in carbohydrates. Most sports nutrition experts recommend a diet of 65% carbohydrate, 25% fat and 10% protein. Also, many recommend that a healthy diet for the average person contain no more than 30% of the calories from fat.

As for protein, they ate about 1.7 grams per kilogram of body weight (0.77 grams per pound). This is well within the range recommended for young athletes (1.4-1.8 g/kg or 0.6-0.8 g/lb).

For the most part, the players’ diets contained ample vitamins and minerals. For example, calcium and vitamin C were well above daily recommendations. The only micronutrient that was lacking was fiber. Players ate only about 70% of what is recommended.

The players drank 3.2 L of fluid per day (108 oz or 0.85 gallons). Considering what is recommended for young athletes to drink throughout the day (2.5 L) and during training (0.15-0.25 L every 15 minutes), the researchers felt that their fluid intake was too low.

The study found that young professional players: 1) do not eat enough calories to meet the energy demands of training and competing, 2) their diet is too low in carbohydrates and too high in fat, 3) they lack adequate fiber in the diet and 4) their fluid intake is low. The authors point out that the consequences of this nutritional strategy could be that the players do not adequately replenish lost energy stores each day. As a result, muscle glycogen would steadily decline over the course of the week, possibly leaving the player weak, tired and lethargic.

They researchers also make a few simple suggestions to remedy this problem. They recommend these players should increase their consumption of whole grain breads and cereals as well as fresh fruits and vegetables. Not only would this increase their total caloric intake but it would also increase their carbohydrate intake as well as their fiber intake. Second, drinking carbohydrate-containing beverages would increase their fluid intake as well. By making these simple changes, players would be better able to replenish and maintain energy stores and avoid possible diet-related declines in performance.

This study also emphasizes the need for players and coaches to routinely monitor diet and performance. By recording and reflecting on their diet and training, deficiencies can be identified. While the study did not address this, it is quite possible that the players assumed they were eating a proper diet. Only by recording and examining what they ate on a daily basis were they able to see that their diets were lacking in several key components. By making the simple changes recommended by the researchers, they can easily transform a somewhat weak diet into a solid one. In return, they should see improved performance on the pitch.

Reference:

Russell M, Pennock A (2011) Dietary analysis of young professional soccer players in 1 week during the competitive season. Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0b013e3181e7fbdd

Note: Mark Russell operates the website http://www.scientific-football.com/