Intermittent fasting as effective as constant dieting for weight loss

The no-feast-only-famine approach to eating isn't for everyone (or most of us) but increasingly scientists and clinicians are finding that fasting benefits our health and longevity, not only our minds, as gurus have long known.

Three men who fasted intermittently were able to stop injecting themselves with insulin within a month of starting the regime, research published this week in the British Medical Journal shows.

A trio of men is not a scientific sample; but the results are the latest in mounting evidence that fasting improves our metabolic health. The impact of fasting seems to be like rebooting our bodies.

For this study two men fasted for a full 24 hours on alternate days, while the third fasted three days a week. They were only allowed tea, coffee, water and broth, and a very low-calorie meal in the evening, on fast days.

For about 10 months they stuck to this pattern "without too much difficulty", reducing their blood glucose levels and losing weight (10%-18%).

Two of them were able to stop all diabetic drugs (one in five days) and the third stopped three out of four of his drugs, the cases studies revealed.

But even people without chronic conditions stand to gain - and lose, in body fat - by fasting, whatever type of regimen they adopt.

Fasting overnight - drinking only water or calorie-free drinks - from 6pm to 10am contributed to weight loss and lowering blood pressure in another small study in the US. On average participants had 350 fewer calories over 24 hours.

One of the easier "fasting" options means cutting down the number of hours you eat in a day, while not restricting what you eat - no dieting. By narrowing their "eating window", people in another UK study lost body fat.

They delayed eating breakfast by 90 minutes and had dinner 90 minutes earlier - and overall ate about 25% less. Their breakfasts moved to on average 9am to 10am and their dinners to 6pm or 7pm.

On average the group of nine who shifted their meals, in the 10-week study, lost more than twice as much body fat as people who did not. Sixteen healthy and overweight individuals took part in the trial.

The times were not compatible long term with family and social meals, the participants said, yet if the meal times were more flexible they would consider following this routine.

Before a climbing holiday last month, I experimented with eating later in the morning for five days, drinking my first cup of coffee black at dawn, and eating breakfast mid-morning at work. I had my last meal at about 9pm or 10pm.

My guinea-pig approach proves nothing though I did get leaner, short term. Of course this didn't last, when on our holiday I drank beer at the end of a day's climbing.

I had more success with sticking to this option - given my opposition to dieting - than another "semi-fast" I volunteered to test, which claims to switch the body into anti-ageing and fat-burning mode.

People on the "fasting-mimicking" study in 2015 by the Longevity Institute of the University of Southern California - who ate a plant-based diet of only 700 calories a day - had a boost in immunity, repair of the body and loss of abdominal fat.

Institute director and study co-author, Professor Valter Longo, wholeheartedly supports it and said his whole family and department had tested it.

Mice in a similar experiment to the humans gorged themselves after the five days of semi-fasting were up, but the health gains they had achieved remained.

Fasting is also important in the Banting diet, popularised in SA by Professor Tim Noakes, an exemplary advocate for it.

He said: "One of the keys to the diet is fasting …People should practise portion control and eat fewer meals a day."

Dietician Irene Labuschagne from the Nutrition Information Centre at Stellenbosch University said that intermittent fasting - for example, every second day cutting your food intake to about a quarter of the normal intake - had been shown to be as effective as constant dieting in protecting the heart and losing weight.

• People are advised to seek medical and professional advice before starting any type of fast - unless they have prior experience or have 100% healthy track record.