Intermittent fasting now the flavour of the month
When Twitter CEO Jack Dorsey tweeted that he does a 22-hour fast daily [dinner only], and recently did a three-day water fast, people hit back, asking how smart this was.
His approach is a stricter version of the 16:8 method – 16 hours of fasting (typically overnight) followed by eight hours of normal eating.
It is no surprise that intermittent fasting is taking off among Silicon Valley geeks and medical professors alike.
After all, neuroscientists have proved this style of eating boosts and protects the brain.
University of the Witwatersrand HIV professor Francois Venter is one of a group of world-renowned scientists and doctors to do this, typically eating normally for five days a week, followed by two days of semi-fasting.
“We are senior researchers but not in the obesity field,” Venter said.
“The data-driven people put their heads together and scientifically reviewed the literature on weight control and decided on [intermittent] fasting.
“It’s flexible to eat a quarter of the normal calories twice a week,” Venter said.
His sole interest in weight is how it affects his rock climbing.
“Two days a week is much easier to do than starving for a week or a month.”
Despite the trend towards intermittent fasting – typically two days a week, 16 hours a day or alternate days – results of a study published in January show it is no better than conventional diets for losing
‘Two days a week is much easier to do than starving for a week or a month’ Francois Venter
WITS UNIVERSITY HIV PROFESSOR
weight. It may be easier to follow than a conventional diet.
It may have greater health benefits – boosting your metabolism, protecting against degenerative brain disease and potentially slowing down ageing – but it is not a shortcut to a slinkier you.
The German Cancer Research Centre and Heidelberg University Hospital ran a trial with 150 obese participants.
Centre researcher Ruth Schubel said: “There are only a few studies on intermittent fasting, but they have come up with strikingly positive effects for metabolic health.
“It made us curious to find out whether these effects can also be proven in a larger group and over a prolonged period – using the 5:2 dietary plan.
“The result may be sobering for all followers of intermittent fasting,” Schubel said.
Both dietary groups lost the same amount of body weight, unhealthy belly fat (visceral fat) and extra fat in the liver, with no significant metabolic differences reported.
What it did reveal is that a small weight loss, by whatever means, is a major health gain.
People who reduced their body weight by only 5% lost about 20% of the dangerous visceral fat and more than a third of the fat in the liver.
Lead scientist Tilman Kuhn said: “For some people it seems to be easier to be very disciplined on two days.”
After the initial adaptation, intermittent fasting has also been shown to improve mood.
An Australian study published in January, on alternateday fasting found it to be effective for weight loss.
But alternate-day fasting could be risky for people with diabetes by impairing the action of sugar-regulating hormone insulin, researchers said at the European Society of Endocrinology meeting in 2018.
Irene Labuschagne, from the Nutrition Information Centre at Stellenbosch University, said: “Any individual on chronic medication or at risk of developing low blood glucose levels [metabolic syndromes, diabetics, training athletes] and pregnant women should discuss fasting with their doctor.
“Prolonged fasting could lead to dehydration or inadequate nutrient intake.”
People had to make sure they avoided too much or too little food during the refeeding phases, she said.