• Body weight [ Time Frame: 0, 6, 12, and 18 months ] [ Designated as safety issue: No ]
  

• Body length [ Time Frame: 0, 6, 12 and 18 months ] [ Designated as safety issue: No ]
  
• Skinfolds [ Time Frame: 0, 6, 12 and 18 months ] [ Designated as safety issue: No ]
  
• Waist circumference [ Time Frame: 0, 6, 12 and 18 months ] [ Designated as safety issue: No ]
  
• Bioelectrical Impedance [ Time Frame: 0, 6, 12 and 18 months ] [ Designated as safety issue: No ]
  
• Energy intake at lunch time [ Time Frame: 0 and 18 months ] [ Designated as safety issue: No ]
  

Rationale: Liquid carbohydrates (including soft drinks as well as fruit juices) are thought to be less satiating then solid carbohydrates (e.g., bread or fruits). The hypothesis is that calories from sugary drinks might not be compensated for by eating less at subsequent meals and body weight would increase. In this way liquid carbohydrates might be one of the causes of becoming overweight and obesity. However, the evidence for a causal relation between sugary drinks and weight gain is inconclusive.

Objective: To test the effect of replacing sugar-containing beverages by beverages low in sugar on body weight and fat mass in children aged 5-10 years.

Study design: A double-blind, long term, randomized controlled trial.

Study population: Healthy school children in the age of 5-10 years old. We consider it unethical to encourage children to drink sugary drinks. Therefore children are only eligible if they already habitually consume 250 mL per day or more of sugary drinks.

Intervention: Six hundred healthy children (5-10 years) will be divided randomly into 2 groups. Group 1 (n=300) receives 250 mL per day of sugar-containing lemonade. Group 2 (n=300) receives 250 mL per day of lemonade low in sugar. The low-sugar drinks are sweetened with artificial sweeteners. The drinks will be consumed during the morning break during the weekdays at school and at home during weekends and holidays. The intervention period will be 18 months. Before the main trial starts feasibility and logistics will be tested in a pilot study. The design of the pilot study will be a 2-month randomized controlled trial in approximately 80 school children aged 5-10 years.

Main study parameters/endpoints: The primary outcomes of the study are the children's body weight (body mass index, corrected for age), waist circumference, skin folds and bioelectrical impedance. These outcomes will be measured four times during the study, at 0, 6, 12 and 18 months. As a secondary outcome we will also assess food intake of the children at lunch time, shortly after the morning break when the children have consumed the study drinks. This outcome will be measured at the start and at the end of the study.