Main study : four groups of subjects ( n = 134 ; age 18-60 years , BMI 22.5-35 .0 kgm ( -2 ) ) consumed 200ml/22kcal foam ( based on pre-study results ) immediately after main meals ( M ) , after snacks ( S ) , in-between snacks and main meals ( I ) or not at all ( control , C ) within 1 day of a reduced-energy meal plan consisting of three main meals and three snacks .