“Fasting is a fiery weapon. It has its own science. No one, as far as I am aware, has a perfect knowledge of it” Mohandas Gandhi
Scientific Merits of Fasting
In the past century alone, much research has been devoted to the study of animals and humans who undergo fasting. A plethora of benefits has been uncovered by researchers, including ketogenesis, the modulation of hormones, attenuated oxidative stress and inflammation, enhanced resistance to stress and autophagy . In fact, studies have been conducted on diseased animal and human models in order to delineate the therapeutic potential of fasting as well. Clinical research has suggested that fasting can improve hypertension (elevated blood pressure) [2, 3], reduce inflammation in rheumatoid arthritis , reverse cardiovascular disease  and insulin resistance (metabolic syndrome) , alleviate the pain of osteoarthritis  and improve markers of quality of life .
Fasting has also shown great benefits regarding aging. Caloric restriction by just 20 to 40% can bring about beneficial metabolic and hormonal changes that increase longevity! In fact, dietary restrictions have been observed to increase the lifespan of mice by a staggering 30 to 50%! How does this happen? Researchers have dubbed this “the flipping of the metabolic switch” . This metabolic switch refers to the body’s shift from glucose utilization to fatty acids and ketones instead. Ketones have been shown to be the preferred energy source for the body and brain during protracted periods of fasting and aerobic exercise . This switch represents a shift from the synthesis and subsequent storage of fat (lipids) to the mobilization and recruitment of fat in the form of fatty acids and ketones for energy expenditure. Indeed, animal studies in recent times have shown reduced overall body weight, total cholesterol, triglycerides, insulin and inflammatory mediators such as interleukin-6 and TNF-α. 4 trials have been conducted in humans – showing significant reductions in weight, reductions in fasting glucose and improvements in LDL and HDL cholesterol [12, 13].
The Future of Fasting
Although mankind has adopted fasting for over 2,000 years, the scientific merits of fasting have only just begun to be realized. The next decade will see even more therapeutic benefits of fasting validated through scientific research. One of these areas is in stem cell or rejuvenative medicine. A recent study showed that short-term (24 hours) fasting induces intestinal stem cell function in mice by inducing fatty acid oxidation. The researchers concluded that fasting promotes the regenerative effects mediated by our stem cells. Stem cells are undifferentiated “parent” cells which are responsible for giving rise to specialized “daughter” cells which function in various ways. Our red blood cells that carry oxygen and our white blood cells that defend our body against microbes are daughter cells from the same parent stem cell produced in the bone marrow .
Fasting also makes cancer cells vulnerable to nutrient deprivation and alter their cellular metabolites to reduce their survivability. Emerging evidence suggests that when combined with chemotherapy and immunotherapy, fasting is a promising strategy to improve cancer outcomes . Fasting has also been shown to prevent the development of cancer by promoting autophagy – the cellular housekeeping mechanism which eradicates damaged cellular proteins and ensures cellular renovation [16, 17].
Fasting is a natural, safe and effective strategy that has a plethora of benefits, ranging from the prevention and treatment of cancer, the retardation of aging through stem cell regeneration, the alleviation of inflammation and pain, the improvement in cardiovascular and metabolic markers of health and overall improved quality of life. Emerging and future evidence is bound to shed more light on the molecular and genetic pathways through which fasting facilitates these miraculous benefits.
- Longo, V.D. and M.P. Mattson, Fasting: molecular mechanisms and clinical applications. Cell metabolism, 2014. 19(2): p. 181-192.
- Goldhamer, A., et al., Medically supervised water-only fasting in the treatment of hypertension. J Manipulative Physiol Ther, 2001. 24(5): p. 335-9.
- Goldhamer, A.C., et al., Medically supervised water-only fasting in the treatment of borderline hypertension. J Altern Complement Med, 2002. 8(5): p. 643-50.
- Kjeldsen-Kragh, J., et al., Controlled trial of fasting and one-year vegetarian diet in rheumatoid arthritis. Lancet, 1991. 338(8772): p. 899-902.
- Horne, B.D., et al., Usefulness of routine periodic fasting to lower risk of coronary artery disease in patients undergoing coronary angiography. Am J Cardiol, 2008. 102(7): p. 814-819.
- Li, C., et al., Metabolic and psychological response to 7-day fasting in obese patients with and without metabolic syndrome. Forsch Komplementmed, 2013. 20(6): p. 413-20.
- Schmidt, S., et al., [Uncontrolled clinical study of the efficacy of ambulant fasting in patients with osteoarthritis]. Forsch Komplementmed, 2010. 17(2): p. 87-94.
- Michalsen, A., et al., Incorporation of fasting therapy in an integrative medicine ward: evaluation of outcome, safety, and effects on lifestyle adherence in a large prospective cohort study. J Altern Complement Med, 2005. 11(4): p. 601-7.
- Fontana, L., L. Partridge, and V.D. Longo, Extending healthy life span–from yeast to humans. Science, 2010. 328(5976): p. 321-6.
- Anton, S.D., et al., Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity (Silver Spring, Md.), 2018. 26(2): p. 254-268.
- Volek, J.S., T. Noakes, and S.D. Phinney, Rethinking fat as a fuel for endurance exercise. Eur J Sport Sci, 2015. 15(1): p. 13-20.
- Patterson, R.E. and D.D. Sears, Metabolic Effects of Intermittent Fasting. Annu Rev Nutr, 2017. 37: p. 371-393.
- Harvie, M. and A. Howell, Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects-A Narrative Review of Human and Animal Evidence. Behav Sci (Basel), 2017. 7(1).
- Mihaylova, M.M., et al., Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging. Cell stem cell, 2018. 22(5): p. 769-778.e4.
- Nencioni, A., et al., Fasting and cancer: molecular mechanisms and clinical application. Nat Rev Cancer, 2018. 18(11): p. 707-719.
- Antunes, F., et al., Autophagy and intermittent fasting: the connection for cancer therapy? Clinics (Sao Paulo, Brazil), 2018. 73(suppl 1): p. e814s-e814s.
- Bagherniya, M., et al., The effect of fasting or calorie restriction on autophagy induction: A review of the literature. Ageing Res Rev, 2018. 47: p. 183-197.