Acute Exposure to a High-Fat High-Sugar Diet Alters Wheel Running Activity

Abstract

BACKGROUND: Literature shows that chronic exposure to a high-fat high-sugar (HFHS) Western diet decreases voluntary physical activity, mainly through decreased duration of activity. PURPOSE: To determine if acute exposures to standard chow and a HFHS diet affect voluntary activity levels in male mice. METHODS: Eight-week- old male C57BL/6J male mice (n=20) were singly housed and provided with running wheels. Wheel running activity was measured daily via mounted odometers. Distance (km) and duration (min) were used to calculate average speed (m/min). Mice were randomly assigned to two experimental groups that alternated between the HFHS diet (20% protein, 35% carbohydrate, 45% fat, with 20% fructose water) and a standard chow diet (24.3% protein, 40.2% CHO, 4.7% fat) in three 5-day cycles followed by two 8-day cycles. At study initiation, Group 1 began with the HFHS diet and Group 2 began with standard chow. At the end of each cycle period, both groups switched to the opposing diet. Data were analyzed using a repeated measures model with distance, duration, and speed for each cycle as dependent variables and diet, group, and diet*group interaction as fixed effects. Alpha value was set a priori at 0.05 and post-hoc tests used Tukey’s HSD. RESULTS: Acute exposure to the HFHS diet decreased speed (p=.0075), while distance (p=.7527) and duration (p=.1077) were not altered. No overall group effects on distance (p=.3670), duration (p=.3747), or speed (p=.5266) were observed; however, animals exposed to the chow diet first (Group 2) showed an increase in activity duration (p=.0040) when exposed to a HFHS diet in all cycles. CONCLUSION: Acute exposure to a HFHS diet only decreased speed, which is surprising given the literature on chronic HFHS exposure that has shown decreases in distance. The observed increase in activity duration in mice that had chow at the initiation of wheel-running exposure (Group 2) suggests that acute and chronic effects of a HFHS diet on physical activity level differ in mice.