A double-blind, randomized trial of the efficacy of replacing sugary drinks by low-sugar alternatives on body weight and fat mass in school children. (WC2008-023)


Starting date: 01/01/2008
a.       Study design
An 18-month, double-blind, randomized, controlled intervention study in 600 school children aged 5-10 years. Six hundred healthy children (5-10 years) will be divided into 2 groups by lottery. Group 1 (n=250) receives 250 mL per day of sugar-containing drinks for 18 months and group 2 (n=250) receives 250 mL per day of a specially developed, identical-looking, sugar-free version of the same drink. The lottery ensures that diet and activity will on average be the same in both groups. The drinks will be consumed during the morning break at school and consumption will be supervised by the teacher to check whether the children actually drink the study drinks. During weekends and holidays children consume the drinks at home. No instructions will be given on food selection or intake so as not to disturb spontaneous adjustments in intake brought on by the study drinks.
b.      Study population
In total 600 healthy school children aged 5-10 years will participate in this study. We aim at children because obesity starts in childhood, and once it is present it is hard to rectify. Also, children are less weight-conscious than adults, and therefore they are less likely to change their food intake or level of exercise when they gain or lose body weight. We consider it unethical to encourage children to drink sugary drinks. Therefore, children are only eligible if they already habitually consume sugar-sweetened beverages. This way, children will replace their habitual drinks with the study drinks, without a need to change their drinking habits.
c.       Instruments
The primary outcomes of the study are the children's body weight (body mass index (kg/m2), corrected for age) and fat mass as estimated from waist circumference (cm), skinfold thickness (mm) at 4 sites, and bioelectrical impedance. Measurements will take place every 6 months and differences between changes in the two groups will be evaluated.