The most effective way to use fasting to lose weight

Telegraph

19-06-2025

Fasting every other day could be the most effective diet to help shave off the pounds, according to a BMJ study.
The analysis found that restricting calories by fasting on alternate days was more effective than a continuous diet reducing intake every day.
The review of data from 99 separate studies involving more than 6,500 people found that on average, those fasting every other day lost 1.29kg more than those dieting each day.
Alternate day fasting involves a 24-hour fast on alternate days and has become more popular in recent years.
Other intermittent fasting approaches to dieting have also grown in popularity, including time restricted eating, where people only eat for a certain number of hours in the day, such at the 16:8 diet involving a 16-hour fasting period followed by an eight-hour eating; and whole day fasting, which includes the 5:2 diet involving five days of eating and two days of fasting periods.
Researchers from Scotland, the US, Canada and Germany wanted to compare fasting methods to continuous energy restriction diets by looking at all of the available evidence.
People involved in the studies had an average body mass index (BMI) of 31 and almost nine in 10 (89 per cent) had pre-existing health conditions.
The research team found that both intermittent fasting diets and calorie restricted diets led to weight loss.
But compared with continuous energy restriction, alternate day fasting was the only strategy to show benefit in body weight reduction, with people on this diet losing 1.29kg more.
The authors said that alternate day fasting showed a 'trivial' reduction in body weight compared with both time restricted eating and whole day fasting.
'Minor differences were noted between some intermittent fasting diets and continuous energy restriction, with some benefit for an alternate day fasting strategy with weight loss in shorter duration trials,' the authors wrote.
'All intermittent fasting strategies and continuous energy restriction diets showed a reduction in body weight when compared with an ad-libitum diet
'Of three intermittent fasting diets, alternate day fasting showed benefit in body weight reduction compared with continuous energy restriction,' they said.
Naveed Sattar, a professor of cardio-metabolic medicine at the University of Glasgow, and who was not involved in the study, said the findings were not surprising 'as there is nothing magical about intermittent fasting for weight loss beyond being another way for people to keep their total calorie intake lower than it would be otherwise'.
'It becomes another lifestyle option for weight management,' he said.
'Whether it is sustainable over the longer term is worth to examine, whereas for those who need to lose much more weight, other options are now clearly available.'
Almost one in three adults in the UK are obese while a further third are considered overweight.
Last week, Prof Sir Stephen Powis, the NHS's top doctor, said that weight-loss jabs such as Wegovy and Mounjaro could be as transformative as statins.
From later this month, GPs in England will be allowed to prescribe Mounjaro, also known as tirzepatide, for the first time.