['To evaluate the effects of a high-fat and low-fat diet on taste sensitivity to oleic acid (C18:1) in lean and overweight/obese (OW/OB) subjects.', 'Randomized cross-over dietary intervention involving the consumption of a high-fat (>45% fat) and low-fat (<20% fat) diet, both consumed over a 4-week period.', 'A total of 19 lean, mean age 33±13 years, mean body mass index (BMI) 23.2±2.2\u2009kg\u2009m(-2) and 12 OW/OB, mean age 39.5±3 years, mean BMI 28±2.6\u2009kg\u2009m(-2), subjects participated in the study, which measured taste thresholds for C18:1, fat perception and hedonic ratings for regular (RF) and lowered-fat (LF) foods before, and following consumption of a high- and low-fat diet.', 'Consumption of the low-fat diet increased taste sensitivity to C18:1 among lean and OW/OB subjects (P<0.05) and increased the subjects ability to perceive small differences in the fat content of custard (P=0.05). Consumption of the high-fat diet significantly decreased taste sensitivity to C18:1 among lean subjects (P<0.05), with no change in sensitivity among OW/OB persons (P=0.609). The hedonic ratings for several RF and LF foods differed following the diets.'] Does recent fat intake modulate fat taste sensitivity in lean and overweight subjects?