DIETARY-FAT AND APPETITE - SIMILARITIES AND DIFFERENCES IN THE SATIATING EFFECT OF MEALS SUPPLEMENTED WITH EITHER FAT OR CARBOHYDRATE

In experiment 1, normal weight male subjects were provided with three types of breakfast consumed in the Human Appetite Research Unit on sep arate experimental days 1 week apart. The intensity of hunger, fullnes s and other subjective feelings were tracked by means of visual analog ue rating scales at intervals during the day. Energy and nutrient inta kes were measured directly from ad libitum test meals consumed at lunc h and dinner. During the rest of the day and until after breakfast the following day, food intake was measured indirectly through weighed fo od records. The test breakfasts comprised a basic meal 184 1 kJ (440 k cal) and the same meal supplemented with similar amounts of either fat (1515 kj, 362 kcal) or carbohydrate (1527 kj, 365 kcal). No differenc es were detected between the effects of the basic breakfast compared w ith the fat-supplemented breakfast. The carbohydrate supplement suppre ssed hunger ratings during a limited period after consumption (the pos t-ingestive window) coinciding with the expected metabolism of carbohy drate. In experiment 2, a direct test of consumption during this post- ingestive window confirmed that the carbohydrate supplemented breakfas t suppressed intake but the fat supplement did not. These results demo nstrate that carbohydrate and fat can produce quite different effects on satiety. Under these experimental conditions the supplement of fat produced no detectable effect on the expression of appetite and illust rates how dietary fat could lead to passive over-consumption of energy . However this. effect may be modified by the particular pattern of fo od consumption during the course of a day.