The well known phrase 'slow and steady wins the race' might not actually be the best motto to live by for those looking to lose weight.
Scientists are now advising against slow but sure dieting in favour of rapid weight loss methods.
They also found evidence which suggests that the idea of shedding too many pounds too fast - which then leads to a cycle of "yo-yo" dieting - is actually a myth.
Losing weight quickly is the best way to achieve slimming goals and not likely to result in greater weight regain than the slow approach, scientists said.
The findings contradict current dietary recommendations that favour slow and steady weight loss.
Australian researcher Katrina Purcell, from the University of Melbourne, said: "Across the world, guidelines recommend gradual weight loss for the treatment of obesity, reflecting the widely held belief that fast weight loss is more quickly regained.
"However, our results show that achieving a weight loss target of 12.5% is more likely, and drop-out is lower, if losing weight is done quickly."
The study looked at 200 obese adults who were randomly assigned to one of two slimming diets.
One was a 12 week rapid weight loss (RWL) programme on a strict diet of 450 to 800 calories a day.
The other was a 36-week gradual weight loss (GWL) programme, which reduced energy intake by around 500 calories a day in accordance with current guidelines.
Participants who lost more than 12.5% of their bodyweight were then placed on a weight maintenance diet for three years.
Those on the rapid diet were more likely to meet their slimming target, with 81% of the group shedding at least 12.5% of body weight.
In contrast, only half of the gradual slimmers achieved this goal.
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Weight regain was about the same for both sets of participants on the maintenance diet.
In each case, about 71% of lost weight was restored after three years.
Writing in The Lancet Diabetes & Endocrinology journal, the authors suggested that the limited carbohydrate intake of very low calorie diets may force the body to burn fat.
Breakdown products of fat burning, called ketones, can suppress feelings of hunger.
Losing weight quickly might also motivate people to persist with dieting and achieve better results, the researchers said.
Commenting on the research in the journal, Dr Corbin Martin and Professor Kishore Gadde, from Pennington Biomedical Research Centre in Baton Rouge, US, wrote: "The study indicates that for weight loss, a slow and steady approach does not win the race, and the myth that rapid weight loss is associated with rapid weight regain is no more true than Aesop's (tortoise and hare) fable.
They added: "Clinicians should bear in mind that different weight loss approaches might be suitable for different patients in the management of clinical obesity, and that efforts to curb the speed of initial weight loss might hinder their ultimate weight loss success."
British dietary expert Professor Susan Jebb, from Oxford University, said: "This is an important and well conducted study.
"It shows clearly that the common claim that more rapid initial weight loss is associated with more rapid regain is false.
"This is important because it will enable professionals to recommend a broader range of treatment options so that people may be more likely to find the one that is best suited to their lifestyle.
"Interestingly, the rapid weight loss group were more likely to achieve their target weight loss and more likely to stick with the program," Susan added.
"These factors are both important to successful weight control."
Naveed Sattar, Professor of Metabolic Medicine at the University of Glasgow, questioned how "gradual" the GWL diet really was.
"For me, gradual weight loss would be a loss of around 3% weight loss at three months before a period of weight maintenance - and then individuals can revert to weight loss if so desired," he said.
"It may be best for the majority of individuals to lose weight even more slowly than in this study and more work is needed in this space to test this."Suggest a correction