Sequential Meals Containing Animal and Plant-Based Saturated Fats Have Differential Effects on Postprandial Gut Hormones but No Impact on Satiety Compared with Unsaturated Fats in Generally Healthy Males: Findings from the Randomized Controlled Crossover CocoHeart Study

Background: Saturated fat (SFA)-rich meals are often linked to elevated postprandial triacylglycerol responses compared with unsaturated fats. Despite the growing popularity of coconut oil in the United Kingdom diet, effects of this SFA-rich oil on postprandial lipemia and physiological appetite responses are unclear. Objectives: This study compared sequential high-fat test meals rich in butter and coconut oil with a vegetable oil blend (safflower and olive oil) on postprandial triacylglycerol (primary outcome), lipids, glucose, and gut hormones responses, and physiological measures of appetite in healthy males. Methods: In a single-blind, randomized acute 3-armed crossover study, 13 males (53 ± 3 years, body mass index 24.4 ± 3.0 kg/m²) consumed sequential test meals containing SFA-rich oils/fats or a vegetable oil blend (breakfast 53.6 g and lunch 33.6 g fat) on 3 occasions, each separated by a 4-wk period. Blood samples and satiety ratings were collected prior to and at regular intervals over 480 min post-test breakfast. Blood pressure and arterial stiffness were measured at 0, 150, 300, and 480 min. Postprandial data were analyzed using linear mixed models and satiety ratings using analysis of covariance. Results: Postprandial triacylglycerol, glucose, insulin, ghrelin, blood pressure, and arterial stiffness or perceived satiety responses were similar between the test fat/oils. The incremental area under the curve (iAUC) for the postprandial glucose-dependent insulinotropic polypeptide response was higher with vegetable oil compared with the SFA-rich meals whereas the glucagon-like peptide-1 response was lower after the butter than coconut and vegetable oil-rich meals (P ≤ 0.012). The iAUC for the peptide YY response was lower after butter than coconut oil-rich meals (P ≤ 0.048), but not different compared with vegetable oil. Conclusions: Despite varying fatty acid compositions, postprandial triacylglycerol responses were similar between fats/oils. Our findings suggest that butter and coconut oil have differential effects on gut hormone responses compared with unsaturated fats without an impact on satiety in generally healthy males. Trial registration number: NCT05264233.