Beyonce, Benedict Cumberbatch and This Morning presenter Phillip Schofield have all praised it at one point or another.
But the 5:2 diet, and other calorie-restricting regimes, don't work in the long-term and are simply a waste of time and money, an expert today claimed.
The diets, endorsed by a host of celebrities, have risen in popularity in recent years as people desperately try to battle the bulge.
However, Dr Jason McKeown, an Irish neuroscientist, explained how getting a trim figure is near-on impossible through cutting back calories.
He told MailOnline: 'By all means, try dieting – but don’t blame whatever scheme you’ve bought into when it doesn’t work.'iPhone transfer software
Dr Jason McKeown, an Irish neuroscientist, explained how getting a trim figure is near-on impossible through cutting back calories
Dr McKeown, of the University of California San Diego’s Brain and Cognition Centre, argued brains have been 'programmed to feel comfortable' when weight increases.
But the brain, particularly the 'mission control' hypothalamus, defends that higher range when someone seeking to lose weight tries to diet.
'Unfortunately our junk-food heavy diets have reset our brains and made this range higher – hence our bulging waistlines,' Dr McKeown added.
'Stimulating the hypothalamus in your brain can help you overcome this issue and help you achieve a leaner, healthier more athletic physique.'
It comes after Duncan Selbie, chief executive of Public Health England, stressed back in March that 'Britain needs to go on a diet'.
His comments came alongside a Government drive to slash portion sizes of some of the nation's most popular foods, including pizzas and ready meals.
Officials are aiming to cut calorie consumption by 20 per cent by 2024. Eating too many calories is a known driving cause of obesity.
Figures suggest around half of Britons are on a diet at any one time - mostly women.
Beyonce has previously praised the 5:2 diet (pictured at Coachella festival earlier this month)
The trendy diets, endorsed by a host of celebrities, including the actor Benedict Cumberbatch, have risen in popularity in recent years
Thousands of Britons are making up bizarre reasons to avoid having to go to the gym, a poll suggests.
The survey of 2,000 adults found 82 per cent admit crafting an excuse to skip the weights at least three times a week.
'I need to do some housework' was used by a fifth of respondents, while 'I need to Netflix and Chill' was the go-to for 10 per cent.
The poll, commissioned by fitness app Esquared, found 'it's too much hassle' was the most popular excuse, used by a third of people.
And four per cent even admitted they told friends how they would 'prefer to social stalk' their ex-partner than go to the gym.
Esquared said 'some people are Olympic-level excusercisers'.
Several diets have tapped into calorie-cutting, including the 5:2, made famous by medic and journalist Dr Michael Mosley.
It involves eating normally for five days a week and then on two days a week cutting intake severely to just 600 calories a day.
Various medical studies have backed it up and found it can work - but Dr Mosley has previously admitted no studies have yet been published proving that intermittent dieting leads to long-term weight loss.
Speaking last year, Dr Mosley said: 'On the 5:2 I lost 9kg and reversed my diabetes. The TV presenter Phillip Schofield told me that it has become a way of life for him.
'I’ve read in the press that it has been embraced by celebrities such as Beyoncé, Benedict Cumberbatch, Liv Tyler, Ben Affleck and Christie Turlington.
'I have also had messages of thanks from thousands of people, ranging from, "I lost 40lb and a year later the weight is still gone" to "I can now take my jeans off without undoing them and I am happy to do so if anyone wants to watch!"'
Several diets have tapped into calorie-cutting, including the 5:2, made famous by medic and journalist Dr Michael Mosley