Short-term effects of standard weight management advice and of the 5-2 diet delivered in self-help or group support format

Plain English summary of protocol

Background and study aims
The 5:2 diet consists of limiting food intake to 500 calories in women and 600 calories in men on two non-consecutive days per week. The diet became popular with extensive reports of success on social media, but there is no scientific evidence so far on whether it works. A number of clients at our weight clinic have reported their experience with the 5:2 diet and we have now also tested it in clinical practice. This identified some barriers such as finding suitable foods and planning meals for the fasting days, but the main hurdle to carrying out the 5:2 diet is the hunger and discomfort on the fasting days. Our experience confirms that people who stick with the programme typically learn to cope with the fasting days well, especially once they see the positive results. We now believe that the diet can be effective with some clients even in its usual self-help format, but that it is likely to work better if group support is included to help people stick with the plan over the first few weeks. This is because after this initial period, the diet should get much easier to maintain without further external support. The aim of this study is to assess the initial effects of the 5:2 diet compared to state-of-the-art standard brief advice, and also to assess the effects of the 5:2 diet when delivered in self-help format and when accompanied by group support. Apart from assessing effects on weight, the study will also provide information on effects the 5:2 diet has on exercise levels and healthy eating.

Who can participate?
Patients aged 18 and over who are overweight or obese (BMI ≥30kg/m2, or BMI≥28kg/m2 with other illnesses [comorbidities])

What does the study involve?
Participants are randomly allocated to one of three groups.
The first group receive a 20-minute session on the 5-2 plan and a written guide on how to use it with recommendations for internet resources along with a leaflet listing local resources for exercise. Participants are encouraged to purchase and use pedometers to increase their exercise levels and to assess their weight weekly. Participants are asked to reduce their energy intake on two non-consecutive days per week to 500 calories for women and 600 calories for men.
The second group receive a brief explanation of the 5:2 plan and are booked for six weekly group support sessions. The sessions focus on helping clients to adhere to 5:2, share coping and fasting strategies and maintain motivation. Each session lasts for about one hour and groups comprise of 10-20 participants. Participants also receive a leaflet listing local resources for exercise and are encouraged to purchase and use pedometers to increase their exercise levels and to assess their weight weekly. Participants are asked to reduce their energy intake on two non-consecutive days per week to 500 calories for women and 600 calories for men.
The third group receive a 20-minute session with an advisor focusing on healthy eating and physical activity and instructions on using the ‘Facts not Fads’ and the ‘Get Active, Stay Active’ British Heart Foundation self-help guides, supplemented by the NHS Change 4 Life series of booklets and a leaflet listing local resources for exercise. Participants are encouraged to use pedometers to increase their exercise levels and to assess their weight weekly.

What are the possible benefits and risks of participating?
The main benefit to the participant is the chance to try a treatment that could enhance the likelihood of achieving and maintaining a beneficial amount of weight loss. We do not forsee any potential risks to participants.

Where is the study run from?
Queen Mary University of London (UK)

When is the study starting and how long is it expected to run for?
November 2015 to January 2018

Who is funding the study?
Medical Research Council (UK)

Who is the main contact?
Sarrah Peerbux
s.peerbux@qmul.ac.uk

Contact information

Study information

Eligibility

Locations

Countries of recruitment

• England
• United Kingdom

Study participating centre

Sponsor information

Queen Mary University of London (UK)
University/education

Joint Research Management Office
Queen Mary Innovation Centre
5 Walden Street
London
E1 2EF
England
United Kingdom

"ROR"	https://ror.org/026zzn846

Funders

Funder type

Research council

Results and Publications

Study outputs

Additional files

ISRCTN79408248_Protocol_v2.6_26May2017.pdf

ISRCTN79408248_Dataset.sav

SSPS file

Editorial Notes

30/08/2023: Uploaded protocol (not peer reviewed) and dataset.
18/11/2021: Publication reference added.
25/07/2019: The following changes were made to the trial record:
1. The total final enrolment was added.
2. The intention to publish date was changed from 30/01/2019 to 01/01/2020.