People lose 50 percent more weight when they take a two-week break from their diet, a study finds.
Intermittent dieting also helps people maintain their weight loss over time.
Taking a break from a diet and eating freely may help people retain their resolve over a period of time.
Dieting also causes the body’s metabolism to slow down, which makes losing weight more difficult.
Eating normally brings the metabolism back up to regular speed and burns more calories.
The study included two groups of obese men: one group dieted continuously and the other dieted on and off.
Both groups dieted for the same period in total — one group took longer, though, taking two-week breaks.
The results showed that continuous dieters lost 20 pounds (9 kg) compared with 31 pounds (14 kg) among intermittent dieters.
Intermittent dieters were also able to maintain more weight loss for longer (18 pounds less weight, on average, than continuous dieters, six months after the study ended).
Professor Nuala Byrne, the study’s first author, said:
“When we reduce our energy (food) intake during dieting, resting metabolism decreases to a greater extent than expected; a phenomenon termed ‘adaptive thermogenesis’ — making weight loss harder to achieve.
This ‘famine reaction’, a survival mechanism which helped humans to survive as a species when food supply was inconsistent in millennia past, is now contributing to our growing waistlines when the food supply is readily available.”
Shorter breaks from dieting are not as effective, said Professor Byrne:
“There is a growing body of research which has shown that diets which use one to seven day periods of complete or partial fasting alternated with ad libitum food intake, are not more effective for weight loss than conventional continuous dieting.
It seems that the ‘breaks’ from dieting we have used in this study may be critical to the success of this approach.
While further investigations are needed around this intermittent dieting approach, findings from this study provide preliminary support for the model as a superior alternative to continuous dieting for weight loss.”
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in the International Journal of Obesity (Byrne et al., 2018).