Intermittent Fasting: Pros and Cons

August 2, 2022

Fasting has been used for centuries as a means to re-establish health, refocus the mind, and for spiritual renewal. Over the last few years “intermittent fasting” has become popular among medical clinicians and the general public. It is often used as a means to restrict calories and promote weight loss. However, there are other beneficial uses for fasting. Intermittent fasting with a compressed eating window of approximately 8 hours during the day and an overnight fast of 12-16 hours is successfully used as a therapy for digestive problems such as irritable bowel syndrome, inflammatory bowel disease, and small intestinal bacterial overgrowth. The overnight fast in addition to spacing meals 4-5 hours during the day allows the gut to heal while resting and promotes a more efficient migrating motor complex. The migrating motor complex is a neurologically driven process that helps sweep out debris and microbes from the small intestine. It is most active when the gut is in a fasting state.

Studies involving neurodegenerative diseases have found that fasting overnight for 12-16 hours promotes mild ketosis helping to fuel the brain, decrease neural inflammation, and optimize brain mitochondrial function. For individuals with genetic predisposition for Alzheimers, intermittent fasting shows great promise for slowing cognitive decline.

Newer oncology research indicates intermittent fasting timed appropriately around chemotherapy treatments improves the treatment outcomes by protecting normal cells from treatment side effects and sensitizes tumor cells to chemotherapy drugs. Cancer cells are fed by our nutrition and in fasting states these tumors can decrease in size. 

For degenerative or chronic diseases such as diabetes and insulin resistance intermittent fasting can help lower hemoglobin A1C (measurement of average blood sugars over the prior three months) when used in conjunction with a low glycemic diet.

However, as good as fasting can be, it can go terribly awry. There can be detrimental effects of intermittent fasting if attention is not taken to prepare and plan nutrient dense meals when not fasting. With a smaller window to achieve individual nutrient needs, inadequate macronutrient and micronutrient intake is often not optimized. Over time, inadequate antioxidant intake, an extreme calorie deficit, and a low fiber diet will result in a decline in health. For athletes, this can result in poor recovery and disappointing performance. Another bad practice that results from a poorly planned fasting regimen is overeating as the fasting period ends. This can be extreme at times and turn into a true binge creating more gut inflammation and stimulating greater insulin demands. It is important to have a guided nutrition plan that will allow for the benefits of intermittent fasting without creating poor eating habits nor low intake of vibrant whole foods that are needed for true health and vitality. 

It should also be noted that intermittent fasting is not right for everyone, nor every stage of life. Shorter fasting periods are better for some women and pregnant women should not partake in intermittent fasting as the growing fetus needs abundant nutrition.

If you are considering trying intermittent fasting and would like some guidance, schedule an appointment with our Registered Dietician, Katherin Taylor!

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Katherine Taylor registered dietician

Katherine Taylor

Katherine Taylor is the registered dietician at Spruce MD Integrative Medicine. She has advanced training in both lifestyle and functional nutrition along with 25 years experience in nutritional counseling. Katherine believes that proper nutritional assessment and guidance can transform health and create vitality at any age.

Registered Dietician

Integrative and Functional Medicine Providers