LAUSR

Purpose Inconsistent evidence exists for greater satiety after medium-chain triglycerides (MCT) or conjugated linoleic acid (CLA) compared to long-chain triglycerides (LCT). Furthermore, the mechanisms are poorly understood and effects in people with a healthy weight and those with overweight/obesity have not been compared. This study aimed to compare appetite responses in these groups and examine the mechanisms behind any differences. Methods Fifteen participants with healthy weight (BMI: 22.7 ± 1.9 kg·m −2 ) and fourteen participants with overweight/obesity (BMI: 30.9 ± 3.9 kg·m −2 ) consumed a breakfast containing either 23.06 g vegetable oil (CON), 25.00 g MCT oil (MCT), or 6.25 g CLA and 16.80 g vegetable oil (CLA). Appetite, peptide YY (PYY), total ghrelin (TG), β -hydroxybutyrate, and gastric emptying (GE) were measured throughout. Energy intake was assessed at an ad libitum lunch and throughout the following ~ 36 h. Results Neither MCT nor CLA decreased ad libitum intake; however MCT decreased day 1 energy intake ( P  = 0.031) and the 48-h period ( P  = 0.005) compared to CON. MCT delayed GE ( P  ≤ 0.01) compared to CON, whereas CLA did not. PYY and TG concentrations were not different ( P  = 0.743 and P  = 0.188, respectively), but MCT increased β -hydroxybutyrate concentrations compared to CON ( P  = 0.005) and CLA ( P  < 0.001). β -hydroxybutyrate concentrations were higher in participants with overweight/obesity ( P  = 0.009). Conclusion Consumption of MCT reduces energy intake in the subsequent 48 h, whereas CLA does not. Delayed gastric emptying or increased β -hydroxybutyrate concentrations may mediate this.