BACKGROUND: The satiating properties of fat remain poorly understood, particularly with reference to its physicochemical characteristics. OBJECTIVE: To investigate the short-term effects of consumption of yoghurt containing either a novel fat emulsion or normal milk fat, on the energy and macronutrient intakes of non-obese subjects. DESIGN: Two double-blind, placebo-controlled, within-subject crossover studies were conducted three months apart. Twenty-nine (15 F, 14 M) and thirty (16 F, 14 M) subjects participated in Study 1 and Study 2 respectively. In each study, subjects were given in random order, 7 days apart, either a 200g portion of a test (5g of a novel fat emulsion + 1 g milk fat) or control (6g milk fat) yoghurt at 1300 h. At 4h post-consumption subjects were given ad libitum access to a range of foods. Amounts of food consumed by individuals were determined by pre- and post-covert weighing of individual serving dishes. RESULTS: Mean energy intakes were significantly lower after the test yoghurt compared with the control yoghurt in Study 1 (6.4 vs 7.6 MJ; P< 0.001), Study 2 (6.9 vs 7.9 MJ; P<0.001), and for both studies combined (6.7 vs 7.7 MJ; P<0.001). The corresponding fat intakes in Study 1, Study 2 and in the combined studies were all significantly reduced (P< 0.001). Protein and carbohydrate intakes were also significantly reduced in Study 1 (P< 0.05), Study 2 (P< 0.01), and for the combined studies (P< 0.001). CONCLUSIONS: These results suggest that the physicochemical characteristics of small amounts of dietary fat affect short-term satiety.