Crash dieting is the fastest way to lose weight, new research finds.
It turns out that the rate of weight loss doesn’t have any effect on putting the weight back on.
In other words, it is not true that people who lose weight rapidly over a short time will then gain it back quickly.
In fact, people who lose excess weight quicker are more likely to reach the target than those who shed their weight gradually.
Professor Joseph Proietto and his colleague set up a dietary assessment to see if slowly losing weight would result in bigger weight reduction and help maintain the weight loss in the longer term.
For the study, 200 obese adults were enrolled either on a gradual weight-loss (GWL) programme or a rapid weight loss (RWL) programme.
GWL involved a 36-week diet plan based on dietary weight loss guidelines by cutting down 500 calories per day.
RWL consisted of a 12-week diet plan based on a very-low-calorie diet or crash diet for which participants consumed less than 800 calories per day.
The results showed that 81 percent of subjects in the RWL group lost 12.5 percent or more of their weight but only 50 percent of participants in GWL group achieved this amount.
Thereafter, those who lost at least 12.5 percent of their body weight went on a three year diet plan to maintain the weight loss.
The research team found that the speed of weight loss had no effect on the rate or amount of weight regained.
After the weight maintenance period those individuals who lost weight in either the RWL or GWL group regained similar amounts of weight.
The rate of putting weight back on was about 71 percent in both groups within 144 weeks.
Ms Katrina Purcell, the study’s first author, 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 authors think one reason might be that crash dieting contains very low amount of carbohydrates.
Limiting carb intake reduces the feeling of hunger and food craving by activating ketosis.
During this process the fat stored in the body will be used to provide most of the energy.
Moreover, rapid weight loss may encourage people to continue with this type of diet as they can see better and quicker outcomes.
Dr Corby Martin and Professor Kishore Gadde from Pennington Biomedical Research Center, in their commentary on this research, said:
“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 fable.
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.”
About the author
Mina Dean is a Nutritionist and Food Scientist. She holds a BSc in Human Nutrition and an MSc in Food Science.
The study was published in The Lancet Diabetes & Endocrinology (Purcell et al., 2014).