This study was done to determine the relative effects of energy conten
t and weight of ingested food on subsequent satiety and food intake. T
he weight/volume and the energy content of nine preloads were manipula
ted, in a 3 x 3 factorial design, to give three weight levels, 250, 50
0 and 750 g, and three energy levels 0, 1.26 and 2.51 MJ (0, 300 and 6
00 kcal). The weights were varied by the addition of water, while the
energy levels were varied by using yogurt and cream. Each of the 1.26
and 2.51 MJ preloads contained 27 g of protein and 31 g of carbohydrat
es. The 1.26 MJ preloads contained 8 g of fat and the 2.51 MJ preloads
had 41 g of fat. Each of the nine preloads was presented as a lunch t
o 21 female and 16 male subjects. Two hours after the preloads, subjec
ts consumed sweet and savory snacks and various drinks ad libitum from
a buffet. The weight of the preload had a small but statistically sig
nificant effect on feelings of hunger and satiety between preload and
buffet, and on energy intake during the buffet (5.34, 5.05 and 5.04 MJ
after 250, 500 and 750 g preloads). There was a large difference betw
een 0 and 1.26 MJ, but little difference in effect between 1.26 and 2.
51 MJ preloads. Mean energy intakes in the buffet after the 0, 1.26 an
d 2.51 MJ preloads were 6.17, 4.83 and 4.42 MJ. These results suggest
that the weight or amount of food affects subsequent appetite and food
intake, but the effect of energy is stronger. (C) 1996 Academic Press
Limited