Fasting and Exercise in Oncology: Potential Synergism of Combined Interventions

Abstract

Nutrition and exercise interventions are strongly recommended for most cancer patients; however, much debate exists about the best prescription. Combining fasting with exercise is relatively untouched within the oncology setting. Separately, fasting has demonstrated reductions in chemotherapy-related side effects and improved treatment tolerability and effectiveness. Emerging evidence suggests fasting may have a protective effect on healthy cells allowing chemotherapy to exclusively target cancer cells. Exercise is commonly recommended and attenuates treatment- and cancer-related adverse changes to body composition, quality of life, and physical function. Given their independent benefits, in combination, fasting and exercise may induce synergistic effects and further improve cancer-related outcomes. In this narrative review, we provide a critical appraisal of the current evidence of fasting and exercise as independent interventions in the cancer population and discuss the potential benefits and mechanisms of combined fasting and exercise on cardiometabolic, body composition, patient-reported outcomes, and cancer-related outcomes. Our findings suggest that within the non-cancer population combined fasting and exercise is a viable strategy to improve health-related outcomes, however, its safety and efficacy in the oncology setting remain unknown. Therefore, we also provide a discussion on potential safety issues and considerations for future research in the growing cancer population.

Intermittent Fasting and Physical Exercise for Preventing Metabolic Disorders through Interaction with Gut Microbiota: A Review

“…When exercising in a fed state, the body primarily utilizes glucose from the recent diet as the predominant source of fuel. However, when exercising in a fasted state, as a result of the depletion of glucose and glycogen stores, the preferential fuel comes from lipolysis and fat oxidation, particularly the breakdown of intramyocellular triglycerides, resulting in stronger beneficial actions for metabolic health [ 77 ]. Some studies revealed that the combination of IF and exercise increased mitochondrial activity, exacerbated the consumption of stored lipids, and enhanced the lipid reserves in muscle [ 78 ].…”