Design of the nutritional therapy for overweight and obese Spanish adolescents conducted by registered dieticians: the EVASYON study.

BACKGROUND: Dietary treatment for obese adolescents should aim to ensure adequate growth and development, by reducing excessive fat mass accumulation, avoiding loss of lean body mass, improving well-being and self-esteem and preventing cyclical weight regain. The aim of this article is to describe the dietary intervention design and the methods used to evaluate nutritional knowledge and behavior in the EVASYON study (Development, implementation and evaluation of the efficacy of a therapeutic programme for overweight/obese adolescents). METHODS/DESIGN: EVASYON is a multi-centre study conducted in 5 Spanish hospital settings (Granada, Madrid, Pamplona, Santander and Zaragoza), where 204 overweight/obese Spanish adolescents were treated in groups of 9 to 11 subjects over 20 visits. The study was implemented in two stages: an intensive, calorie-restricted period for the first 9 weeks, and an extensive body-weight follow-up period for the last 11 months. A moderate energy intake restriction was applied in the intensive period according to the degree of obesity, on the basis of a balanced diet supplying 50-55% of daily energy as carbohydrates; 30-35% as fats and 10-15% as proteins. In the intensive period, adolescents were prescribed both a fixed full-day meal plan for the first three weeks and a full day meal plan with different food-choices for 6 weeks. Later, adolescents received a flexible meal plan based on food exchanges for the follow-up period until the end of the trial. Data on food intake, dietary and meal-related habits and behavior were collected by means of dietary questionnaires. To analyse nutritional knowledge, adolescents were examined regarding nutrient concepts and food adoitems for a healthy diet with the appropriate tools. Participants were given nutritional information with complementary teaching material, which was available on the EVASYON website (www.estudioevasyon.com). DISCUSSION: The dietary intervention of the EVASYON programme with a moderate calorie restriction for a limited period of time could be a good strategy in treating overweight and obese adolescents and that will be tested further. Moreover, combining fixed plan with free-choice menus may help adolescents and their families to make right decisions for every day meals.