So, is it safe to lose weight quickly? “Yes, absolutely,” says Dr Mosley. “There is a widespread belief that if you lose weight fast, then you will put it on even faster. But is that true? In a recent review article titled ‘Myths, Presumptions and Facts about Obesity’ in the prestigious medical journal, The New England Journal of Medicine, researchers put this claim firmly into the “myths” category.
“After looking at numerous studies which have compared rapid with slow and steady weight loss, they concluded that you would do better to lose it quickly rather than slowly. A recent Australian study backs up these claims. Researchers took 200 obese volunteers and put half of them on a low calorie diet (less than 800 calories a day) for 12 weeks. The other half were asked to cut their calories by 500 a day (enough to lose around a pound a week).
“They were then asked to do this for 36 weeks. There was a very high drop-out rate among the steady dieters: less than half made it to the end of the 36 weeks. Most said they gave up because they were frustrated by the slow rate of progress. By comparison, more than 80 per cent of those in the rapid weight loss programme stuck to it.
“They were then followed for three years. Although both groups put some weight back on, the amounts were similar. Katrina Purcell, a dietitian who led the study, said at the time, ‘Our results show that achieving a weight loss target is more likely, and drop-out is lower, if losing weight is done quickly.’ Rapid weight loss isn’t suitable for everyone and if you do decide to lose weight fast you have to make sure you have the right balance of nutrients in your diet.
“Most rapid weight loss studies are now based on 800 calories a day, which is high enough to be sustainable and give the nutrients you need, and low enough to lead to rapid weight loss and other beneficial health changes. You might worry about getting hungry but most people who fast say that within a very short time their hunger passes. Rapid weight loss encourages your body to switch over to fat burning. It also reduces insulin levels, increases growth hormone and boosts levels of a hormone called BDNF in the brain, which helps improve your mood.
“Right now, under the spectre of this frightening pandemic, losing weight isn’t about being ‘bikini body ready’ for summer. For many people, weight loss is now, quite literally, a matter of life and death.”