New research: on/off diet more effective than constant dieting
A new study has found that people who diet two weeks on, two weeks off lose more weight than those who deprive themselves week in, week out.
It is thought that the on/off approach stops the body from finding ways to compensate for the lack of calories, and so ensures the pounds keep falling off.
The research study
Professor Nuala Byrne, of the Bond Institute of Health and Sport in Queensland, tracked 36 obese men as they tried to lose weight.
Half of the men dieted continuously for 16 weeks, cutting their calories by a third. The others followed a pattern where they dieted for a fortnight, then had two weeks off, then dieted again. Although their programme lasted 30 weeks overall, they only dieted for 16 weeks, the same as the first group.
The men on the on/off diet lost an average of just over two stone – 55% more than the men who dieted non-stop. What’s more, their extra weight loss couldn’t be justified by their programme lasting longer, because they shed very little weight during the rest periods.
Why was the on/off dieting more effective?
Professor Byrne believes the on/off dieters did better because their bodies didn’t switch to an energy-conserving survival mode.
She showed that resting metabolic rate, the amount of energy the body uses when ticking over, dropped less in the men on the on/off diet. This helped to stop their weight loss from levelling off.
She also plans to check if intermittent dieting stops the body from trying to claw back the missed calories in other ways, such as by increasing appetite.
She said: “Given that long-term weight loss is a challenge, we are interested in finding ways to overcome the biological and behavioural impediments to losing weight. The results from our study are encouraging as they suggest providing ‘rest periods’ can overcome some of the compensatory biological factors which reduce weight loss efficiency during continuous dieting.”
She added that the highly-popular 5:2 diet, in which slimmers drastically cut their calorie intake two days a week may have the same effect. However, there is a risk that those following the 5:2 diet will overeat on normal days because they’re free to eat what they want. In contrast, her diet is less extreme and contains instructions for both the ‘on’ and ‘off’ phases.
Professor Byrne said that she believes her diet plan ‘has the potential to appeal to almost anyone’.
The opinion against
Dr Carrie Ruxton, an independent dietician and spokesperson for the Health Supplements Information Service, questioned whether slimmers will have the will power to go back to depriving themselves after having a fortnight off.
She also warned that many British adults are already low in vital vitamins and minerals, such as iron, calcium and vitamin D, and dieting could make it worse.
She said that while she is keen for people to lose weight, they need to get into good habits that they can maintain in years to come. She recommends thinking about vices, such as alcohol and chocolate, and cutting down on them, to get results.
Credit: The Daily Mail.