Skip to main content

I’m often asked if I think the 5:2 diet is as effective as a 7-day energy-restricted healthy eating plan, such as The Greengrocer’s Diet. In terms of weight loss, I think both will achieve similar results, however, I think people prefer the 5:2 diet because it gives them more flexibility than a 7-day weight loss regime and is consequently easier to stick to.

Research from the first randomised evaluation of the 5:2 intermittent fasting diet, conducted by Queen Mary University of London supports this view. The study of 300 UK adults over a one-year period found that people received information on the 5:2 diet in preference to standard GP weight management advice, despite both interventions achieving similar weight loss results.

The findings show that long-term weight loss was similar for those who received 5:2 diet or standard weight management advice with 18 % and 15 % of participants respectively losing at least five % of their body weight at one year. However, when asked to rate each intervention, participants in the 5:2 diet group were more likely to recommend the 5:2 diet to others or were willing to continue with their diet.

Previous evidence suggests that peer support could be important to encourage people to stick to and benefit from the 5:2 diet. To test this, the researchers studied the impact of a weekly support group in addition to the simple 5:2 diet advice. They found that whilst initially, face-to-face support generated better early effects and improved adherence to the 5:2 diet, these effects weakened over time.

Dr. Katie Myers Smith, Chartered Health Psychologist and Senior Research Fellow at Queen Mary, said: “Here we’ve been able to provide the first results on the effectiveness of simple 5:2 diet advice in a real-life setting. We found that although the 5:2 diet wasn’t superior to traditional approaches in terms of weight loss, users preferred this approach as it was simpler and more attractive. Based on these findings, GPs may consider recommending the 5:2 diet as part of their standard weight management advice.”

It’s fantastic when research validates something you believe but could never afford to measure yourself.

The 5:2 diet gives people the flexibility to choose which days they want to restrict their calorie intake and take a more relaxed dietary approach on non-fasting days. They do have to eat healthily during non-fasting days but they can still go out for dinner and enjoy a glass or two of wine without feeling like they’ve blown it.

The 6 week Lighten Up course offers daily step-by-step advice, tools, recipes, and thought-provoking exercises to make the 5:2 diet easier to manage. To further improve the effects and adherence to the 5:2 diet, book an introductory one on one coaching session with 5 follow-up sessions. Select the Intro session + 5 follow up sessions pack and get 50% off a Lighten Up Course

For further information, or to book a complimentary 10-minute chat with Judy on the best approach for you, email:

Story Source:
Materials provided by Queen Mary University of London. Note: Content may be edited for style and length.
Journal Reference:
1. Peter Hajek, Dunja Przulj, Francesca Pesola, Hayden McRobbie, Sarrah Peerbux, Anna Phillips-Waller, Natalie Bisal, Katie Myers Smith. A randomised controlled trial of the 5:2 diet. PLOS ONE, 2021; 16 (11): e0258853 DOI: 10.1371/journal.pone.0258853
Cite This Page:
Queen Mary University of London. “Brief 5:2 diet advice is as effective as traditional GP advice, but people like it better, according to new study.” ScienceDaily. ScienceDaily, 17 November 2021.


Leave a Reply