Investigating the Effect of Acute Fat Ingestion on Young, Healthy Adults: A Dose Response Study

Abstract

The long-term consumption (several weeks) of a high-fat diet has been shown to disrupt glucose metabolism and give rise to metabolic diseases, such as type 2 diabetes. Shorter-term high-fat diets (e.g., 3-7 days) also lead to metabolic dysfunction; however, there is a lack of information regarding whether a single high-fat meal can disrupt metabolism in the hours immediately following consumption. Therefore, we investigated the initial metabolic changes that occur during the acute (7-hour) postprandial period following isocaloric meals of differing fat quantity in young, healthy adults. We compared the postprandial availability of metabolites during the five hours following consumption of a 25, 50, or 75% fat meal, and then initiated a two-hour 75 g oral glucose tolerance test (OGTT) to assess glucose handling. Nine recreationally active participants (n=7 male/n=2 female, age = 21 ± 6 years, BMI = 24.1 ± 2.7 kg/m2, VO2peak = 43.3 ± 2.9 and 38.3 ± 4.5 mL/min/kg for males and females, respectively) participated in this three-way, randomized, cross-over study. We found that postprandial area under the curve for glucose and insulin during the first five hours post-consumption was inversely related to the fat quantity of the meal; specifically, the meal with the highest fat content had the lowest postprandial glucose and insulin concentrations (1183 mM*300 minutes and 7,090 µIU/mL*300 minutes, respectively). However, meals with higher fat content were associated with reduced glucose tolerance during the OGTT. Over the entire seven-hour period, triglyceride concentrations were higher following the 75% (599 ± 251 mM*420 min) compared to the 25% fat meal (372 ± 150 mM*420 min, p=0.023). These results suggest that a single high-fat meal differentially affects the postprandial availability of glucose and lipid metabolites and acutely reduces glucose tolerance in young, healthy adults. This study has deepened the understanding of the early metabolic changes that follow high-fat consumption which could lead to the emergence of early-stage interventions that prevent or delay the development of metabolic diseases.