Effect of high-fat meals and fatty acid saturation on postprandial levels of the hormones ghrelin and leptin in healthy men

Objective: Ghrelin and leptin play a role in control of food intake and adiposity but mechanisms regulating these hormones in man are poorly defined and evidence that dietary fats may have adverse effects is inconclusive. We investigated whether high-fat meals, which differed in saturated fatty acid (SFA) content acutely modified these hormones. Design: Randomised, double-blind, crossover trial. A high-fat (HF) test meal ( 5974 g fat; 71% of energy as fat) was given for breakfast on two occasions. Meals comprised either high (similar to 70: 30) or low (similar to 55: 45) saturated: unsaturated fatty acid ( SFA: USFA) ratio. Fasting and postprandial measurements of serum total ghrelin (RIA), leptin (enzyme-linked immunosorbent assay ( ELISA)) and insulin ( RIA) were made over 6 h. Postprandial measurements were also made at 10 and 24 h following a fat-exclusion lunch, snack and dinner. Subjects: A total of 18 lean, healthy men. Results: There was no significant effect of the fatty meal ( time, P>0.05), nor a differential effect of SFA: USFA ratio (treatment* time, P>0.05) on ghrelin over 6 h. Leptin decreased in response to both HF treatments ( time, P<0.001) but increased SFA content did not further inhibit hormone secretion ( treatment* time, P>0.05). There was no significant correlation between ghrelin or leptin and circulating insulin ( P>0.05). Conclusion: We conclude that HF diets may adversely effect serum leptin, although the circadian decrease may account in part for this response. Increasing dietary SFAs had no deleterious effects on leptin or total ghrelin.