Children's food intake was recorded over 3 'test' lunchtime meals at school at weekly intervals. The study was part of a three-day repeated measures study of intake regulation, so on two out of the three days (Days 2 and 3), children were given a 200 ml orange squash drink prior to lunch. On one day this squash contained 5 kcal and on the other day the squash contained 174 kcal; drink conditions were counter-balanced across days. On Day 1 children received no preload drink, forming a control condition. Children participated in all conditions providing they were present on the day in question. Actions taken to account for the preload design are described in the Results section.
The test meal comprised weighed portions of chicken slices, cheese, bread roll with margarine, cheese crackers, chocolate biscuits, grapes and tomatoes or carrot sticks, served cold and presented to each child in an individual compartmented container. Tomatoes had been planned for all meals, but in the first class visited, a large number of children reported disliking tomatoes, so children in the remaining 4 classes were given sticks of raw carrot instead. To maintain consistency, children in the first class were given tomatoes at all subsequent meals. Children were not required to 'clean their plates, but were told to eat as much or as little of the meal as they wished.
Extra pre-weighed portions of bread rolls were offered when children had finished their original servings and unlimited water was provided. Children were observed throughout the meals in order to ensure that food was not shared. Children raised their hand to indicate when they had finished their meal and containers were then collected by researchers and sealed. Foods were subsequently weighed to establish intake in grammes of each food type. Energy content (kcal) of processed foods (chicken slices, cheese slices, cheese crackers, and chocolate biscuits) was calculated using manufacturers' information. McCance and Widdowson's 'The Composition of Foods' [11 ] was used to calculate energy content of the remaining foods (bread, grapes, tomatoes and carrots).