Three-Day Dietary Manipulation in Multiple Sclerosis Exercise and Fatigue Outcomes

Background: In persons with multiple sclerosis (MS), the effect of nutrition on exercise performance and fatigue remains unknown. The objective was to determine whether a 3-day diet high in triglycerides (FAT) compared with a 3-day diet high in carbohydrates (CARB) would improve fatigue and exercise performance in persons with MS. Methods: A randomized controlled crossover design was incorporated to study FAT versus CARB on submaximal cycling endurance (60% of peak oxygen consumption), substrate utilization, and fatigue in 12 persons with mild-to-moderate MS (Expanded Disability Status Scale score, 2.0-5.0) and 12 age and sex-matched controls. Results: There were no differences in cycling time between diets in either group (P =.29). The MS group had no changes in fatigue between diets (P =.64); the control group demonstrated increased total mental fatigue after FAT (P =.05). The control group increased carbohydrate oxidation by 24% at rest and 13% during exercise after CARB. Similarly, the control group significantly increased fat oxidation after FAT by 22% at rest and 68% during exercise (P =.01). These changes were not seen in the MS group. Compared with controls, persons with MS oxidized approximately 50% less fat during exercise after FAT (P =.05). Conclusions: Neither CARB nor FAT altered submaximal exercise performance or baseline fatigue in the MS group.