The aim of the study was to provoke cephalic and metabolic responses by oral fat stimulation with different high-fat meals in the postprandial state. A randomized parallel design was executed with three groups of subjects (twenty-six women and ten men; twelve subjects per group). Oral fat stimulation was achieved by the modified sham feeding (MSF) technique. Five hours after a high-fat breakfast, the subjects were given one of three test meals in random order: a high-fat lunch, water or the same lunch as the MSF. The main fat sources in the high-fat lunch and MSF were olive oil, linoleic oil and oleic oil. For 3h after the test meal, blood samples were taken for analysis of metabolite, and visual analogue scales of appetite profile were completed. A cephalic response appeared to be achieved by MSF in that we observed a relative increase in insulin and glucose; this response lasted up until 90min, indicating possible vagal stimulation. NEFA increased significantly after MSF compared with water ingestion in the case of olive oil (p<0·0001) and linoleic oil (p<0·05), but not with oleic oil. MSF provoked a significantly higher increase in triacylglycerol and glycerol levels compared with water ingestion in the case of linoleic oil (p<0·05). Satiety was significantly increased in the eating condition and in the MSF condition (p<0·0002, all oils) compared with water ingestion. We conclude that cephalic and perhaps vagal stimulation by different fats increased the concentrations of the metabolites and stimulated satiety, with linoleic oil showing the strongest response.

In a randomised, single blind, placebo-controlled crossover design study, we investigated whether healthy, non-smoking, dietary unrestrained women (n 24), divided into linoleic acid tasters (LAT, n 14) and linoleic acid non-tasters (LANT, n 10), differed in food intake regulation when linoleic acid was added to ice creams. The determination of subjects as LAT or LANT was done using a 10μM-linoleic acid solution. The ice creams were characterised by the subjects and a taste perception test using the triangle test was conducted three times. Food intake and appetite were measured using the universal eating monitor. LAT and LANT did not differ in characterisation or in taste perception of the ice creams, even though LAT were able to increase their ability to discriminate between the ice cream with linoleic acid from the one containing oleic acid. No effect of LAT status or type of ice cream was found for hedonic value of the ice creams. Linoleic acid taster status did affect food intake regulation. For LAT, but not LANT, the amount eaten was a function of Δsatiety. Subjects ate by weight of food and not by energy content. In conclusion, differences in food intake regulation were seen between LAT and LANT, in that the amount eaten by LAT was a function of Δsatiety, but was not for LANT.