Monday, March 5, 2012

Nutrient Intake of Spanish Youth Players

It is clear that a player’s diet can affect his or her performance on the field. A diet that is high in fat and low and carbohydrates can leave a player lethargic and without enough “energy” to compete at a high level. This idea is backed by years of research both in the laboratory and on the playing field. Despite this, players still do not eat a proper diet. In a new study, Researchers at the Universidad CEU San Pablo in Madrid performed a detailed analysis of the dietary habits of youth players. As with previous studies, they found that the diets of these players lacked the optimal amounts of carbohydrates, fats and proteins.

The subjects of the study were young male players (aged 16-21 years) from a junior Spanish First Division club. All were asked to self-record their dietary intake for six consecutive days (a full week, excluding match day). What makes this study unique is the level of detail and precision in the dietary records. Players were given food record questionnaires as well as food-weighing scales. They were then instructed on how to record both the types and precise amounts of foods eaten during the week. They were also instructed not to change their eating habits but to eat the same foods that they normally eat. After the recording week, food records were analyzed by the research group to determine how many calories were consumed and whether those calories came from carbohydrates, fats or proteins.

This group of subjects was clearly fit. The average body fat percentage was 10.5%, with goalkeepers having slightly higher values (11.8%) and fullbacks slightly lower (9.9%). All positions also scored high on the Yo-Yo test of intermittent endurance, with the goalkeeper slightly less fit.

As a group, these players consumed nearly 3000 calories per day (38.5 cal per kg of body weight or 17.5 cal per lb). This did not vary between field positions but the goalkeepers consumed fewer total calories that the other positions. While energy expenditure was not measured, this amount of calories consumed per day is probably below what is needed to replenish the energy expended on a daily basis (>3500 cal per day).

The analysis of dietary components showed that as a group, these players consumed less than the recommended amounts of carbohydrates and more than the recommended amounts of fat. For trained soccer players, it is recommended that 55-65% of total calories come from carbohydrates and less than 25-30% from fat. In this group of players, only 45% of their calories come from carbohydrate and 37% from fat. Protein intake was also slightly higher than recommended, 17% versus 10-15%. Thus, the macronutrient intake (carbohydrates, fats and proteins) was less than ideal.

The researchers also found that 55% of the players’ calories came from cereals, potatoes, meat, poultry, milk and dairy products. Without taking preparation into account (e.g. fried chicken versus baked), these are all solid choices that should be included in the diet. However, the researchers also found that 25% of calories came from oils, biscuits, sweets, sweeteners, and pre-cooked foods. Since these items tend to be high in fat or high in simple sugars, they are not solid choices and should be limited to far less that 25%. What is more troubling is that only 1-2% of the players’ calories came from vegetables. A lack of vegetables in the diet not only reduces carbohydrate intake but also limits vitamin and mineral intake.

The overall conclusion from this study is that the caloric intake of these players is less than needed and the macronutrient intake (carbohydrates, fats and proteins) is less than optimal. This conclusion has been reached by others and highlighted on the SSO (Article 1, Article 2). Clearly players need to improve their diets. How can this be accomplished? The authors of the study suggest that the answer lies in education. Players need to understand how the composition of their diet affects their game, that a diet high in carbohydrates and low in fats yields peak performance.

Players also need to understand the food selection process. This is often overlooked in many educational programs – the concepts are taught but specifics are lacking. Few players realize what types of foods that they eat on a regular basis and many do not understand how to make proper food choices. For example, using the food records take from the Spanish players, an obvious suggestion is to reduce the amount of sweets and precooked meals eaten as well as foods cooked in oil (fried). These should be replaced by increased servings of vegetables (preferably fresh). Not only would this reduce the intake of fats but increase the percentage of carbohydrates in the diet (as well as add vitamins and minerals). The researchers emphasize that such a focus on the selection of specific foods and behaviors should be the focal point with young players.

Coaches can play a unique role in affecting the diets of young players, specifically players in their early teens. By making players be aware of what types of foods should be eaten and which should be avoided, it may be possible to improve their diets in terms of both total calories and the optimal percentages of carbohydrates, fats and proteins. There is little doubt that will improve performance. More importantly, instilling proper nutritional habits early in the player’s life can carry into adulthood and led to a healthy lifestyle. Thus, nutritional education can have both immediate and life-long benefits.

Iglesias-Gutierrez E, Garcia A, Garcia-Zapico P, Perez-Landaluce J, Patterson A, Garcia-Roves M (2012) Is there a relationship between the playing position of soccer players and their food and macronutrient intake? Applied Physiology, Nutrition and Metabolism, 37: 225-232.

Further Reading:

The SCIENCE Behind Soccer Nutrition
The SCIENCE Behind Soccer Nutrition: Diet and Training Journal