The Merits of Fasting

First published AUG 18, 2022Updated 19 minutes ago

Health

Fasting is a concept that inspires fear, but if enough like-minded New Zealanders are prepared to band together one day a year and engage in a 24-hour fast, we could overcome negative attitudes towards this ancient practice, argues Professor Doug Sellman

The topic of fasting often prompts incredulous reactions such as:

“Going purposely going without any calories for 24-hours – why would anyone want to do that … besides, isn’t it bad for you?”

“Won’t you go hypoglycaemic (low blood sugar) and have no energy? My partner gets ‘hangry’ just half an hour late for a meal; what would they be like for a whole day?”

But why are people wary of fasting?

First, there is a lot of misinformation and unnecessary fear around the practice. However, I think a deeper reason is found in the way our modern Western culture teaches us the more we consume and acquire the happier we’ll be.

Going without goes against the grain, and the modern intemperate lifestyle is reflected in the continuous daily pattern of overeating – breakfast, morning tea, lunch, afternoon tea, dinner, and supper.

And then we wonder why we have an epidemic of obesity and weight-related medical conditions. But there is change in the air. And the rediscovery of fasting is, I sense, part of this new awakening.

This year, a group called WELOVEFASTING are proposing an inaugural National Fasting Day on September 5, aimed at people who want to experience a fast in the company of other health-conscious New Zealanders, and contribute to the promotion of this free, health-enhancing activity – fasting.

Regular fasting is an excellent thing to do in order to lose weight and feel refreshed, and is thought to also help protect against chronic lifestyle diseases such as Type2 diabetes, coronary heart disease, various cancers and Alzheimer’s disease.

Fasting is well represented in the wisdom traditions of the past. Pythagoras, Plato and Hippocrates advocated fasting for mental clarity, general health and an antidote to disease respectively. And fasting is a feature of six of the eight major religions of the world for spiritual and physical health.

I came to the topic late in my medical career, after spending a decade of research on food addiction and obesity. I chanced upon a YouTube video titled Science of Fasting and was amazed I hadn’t heard about the long-standing human research conducted in Germany, Russia and the USA described there.

This set me on a path of reading, and I found that fasting is a relatively unresearched area (there is not a lot of money to be made out of fasting) and there remain a lot of unanswered research questions.

However, I did find out that fasting increases metabolic rate in contrast to calorie restriction that over time stunts metabolic rate. Fasting breaks insulin resistance, stimulates the production of growth hormone protecting lean muscle, reduces inflammation, and enhances the body’s rejuvenation system through a process called autophagy and other mechanisms.

A recent major review of 43 randomised controlled studies of fasting documents multiple positive outcomes from regular fasting.

I have also come to realise that fasting has been the norm for the vast majority of the time humans have existed (pre-agriculture). Our mammalian metabolism has evolved in the context of a struggle to find enough to eat.

In particular, with a continuous eating pattern, featuring little fasting beyond the eight-hour fast most people engage in each night, there is a degree of insulin resistance in many of us, a proportion in whom this insulin resistance morphs into the metabolic chaos we term Type2 diabetes.

Continuous eating patterns are associated with weight-gain and increased inflammation in the body, a key factor in the aetiology of chronic lifestyle diseases.

I now regularly fast and I’m part of an online group of New Zealanders called WELOVEFASTING, out of which this idea of a National Fasting Day emerged. We have chosen the first Monday of Spring because it symbolises new beginnings. It is also a work day for many, which is excellent for keeping busy, and many cafes and restaurants are also closed.  

The fast will begin after dinner on Sunday September 4 and will be broken 24 hours later at Monday evening dinner on September 5. One fast won’t produce instant health, but it will draw your attention to your relationship with food. For optimal health regular fasting needs to be combined with healthy eating, good daily activity levels, and excellent sleep.

Advice on fasting

Fasting is not indicated for people under the age of 20, or slim people with a BMI less than 20. Anyone with significant medical or psychiatric conditions should consult their doctor before participating.

Otherwise all are welcome to join us in this day off food and calorie-containing drinks. The best preparation is to clean up your diet (restrict highly processed food and alcohol) and have a few practices at delaying break-fast – till lunchtime is good.

Jumping straight into a 24-hour fast would be like going for a 5km run from not having run even 200m for some years. On the day of the fast ensure you drink the equivalent of about eight cups of water. Tea and coffee are considered okay so long as no more than a small splash of milk is added.