A naturopath’s thoughts on fasting

Technically, fasting is defined as consuming no calories of food whatsoever, allowing only the ingestion of water, coffee, tea or other non-caloric liquids during fasting periods. With that said, some fasting regimens allow up to 500 calories of food on ‘fasting’ days, such as Michael Mosley’s ‘5:2’ regime. Another regime gaining popularity is juice fasting, where drinking juices while you fast is permitted, and can last up to 10 days.

First, we need to ask what is really the point of participating in a fast. With obesity endemic around the globe, it seems fasting could play a positive role but does denying our bodies’ nourishment provide any real physical or mental benefits? When you scour the medical journals, talk to the experts or people who have taken part in studies, the simple answer appears to be a resounding ‘yes’. And it also seems that fasting is no longer just for people who can afford to go on juice cleanses, or desire that bikini body. Fasting is now seen as a highly relevant lifestyle strategy to treat and prevent many chronic diseases. Beyond this benefit, it can also promote greater mental clarity and focus, and has even been shown to extend life expectancy.

Valter Longo, the Director of the Longevity Institute at the University of Southern California, initially studied fasting in mice and showed that two to five days of fasting each month reduced biomarkers for diabetes, cancer and heart disease. The research has since been expanded to people, where scientists saw a similar reduction in disease risk factors.

Dr. Longo and Mattson agree that one of the key reasons there is such an improvement in key biomarkers is due to the effect fasting has on lowering insulin and another hormone called insulin-like-growth-factor, or IGF-1, which is linked to cancer and diabetes. Lowering these hormones may slow cell growth and development which, in turn, helps slow the aging process and reduces risk factors for disease.

This process is often referred to as ‘fat burning’, which is not the same as that tempting setting which appears on a gym treadmill. To burn fat we have to eliminate our store of glucose, which can only happen when we have been without food for a minimum of 10 hours. Fat is one of the most useful types of fuel to burn, as it’s not only a clean source of energy but also a more slow-burning one – hence the increase in energy levels people often experience when they regularly partake in intermittent fasting protocols. During this process, the fat is converted by the liver into compounds known as ketones, a great energy source that burns even more efficiently than glucose. Dr. Ludwig describes this physiological process as like running on ‘high-octane gasoline’.