Group programmes for weight loss may be more effective than one-to-one sessions

People with obesity may be more likely to lose weight if they attend group sessions for weight loss programmes, rather than having one-to-one support. New research found that people attending groups had more treatment time and were more likely to lose enough weight to make a difference to their health. 

Much previous research has established that the most effective way to lose weight is through a programme that includes behaviour change with diet and physical activity counselling. However, there is little recent evidence to show how these programmes should be delivered. Before this study, it was not clear whether programmes work better when people have one-to-one support (for example from a doctor, nurse, dietitian or a health coach) or when they attend group sessions.

This research pooled the results of studies comparing group programmes with one-to-one programmes for weight loss. It found that people in groups were more likely to lose at least 5% of their body weight after a year (equivalent to someone weighing 100kg losing 5kg). This is important, because previous studies have shown that when people who are carrying excess weight lose this percentage of their body weight, it makes a big difference to their health.

The research may be included in the evidence review used to inform national guidelines for obesity and weight loss, which are being revised and are expected to be published in 2023.

What’s the issue?

Around one in four adults in the UK is living with obesity. The condition increases the chances of other medical conditions including diabetes, heart disease, stroke and some types of cancer. Obesity reduces life expectancy and impacts on people’s quality of life. It costs the NHS and society vast amounts. Previous research has shown that relatively modest levels of weight loss make a difference.   

The most effective first treatment for obesity is through a programme that includes behaviour change alongside advice on diet and physical activity. People are also more likely to lose weight with support.

How best to provide support, however, has not been clear. Groups may offer social support which can facilitate behaviour change. On the other hand, in one-to-one sessions, a practice nurse, dietitian, GP or health coach could offer personalised advice.

This review of the evidence aimed to find out which type of support works best and should be recommended for most people. 

What’s new?

Researchers found seven studies which compared group and one-to-one programmes for weight loss. Their review included 2,576 people in total, in studies carried out in the UK, the US, Australia, Germany and Spain. 

The review showed that after one year of treatment, people who attended group programmes achieved more weight loss than those who had one-to-one sessions. 

Compared to those having one-to-one sessions, people in group programmes:

    • lost on average 1.9kg more weight 
    • were more likely (58% more) to lose at least 5% of their body weight.  

One reason for the difference could be that most people in groups had more time with the clinician (or whoever delivered the programme) than those treated one-to-one. People in groups had 12 to 55 hours of treatment time, while those receiving individual treatment had 2.5 to 11 hours. 

Why is this important?

If more people with obesity were treated in groups rather than in one-to-one sessions, the NHS should be able to treat more people. This research shows that groups might also be more effective. Successfully treating more people with obesity could improve the quality of life of individuals and reduce the numbers needing treatment for diabetes, heart disease, stroke and cancer. This would reduce the cost of obesity at an individual, NHS and societal level. 

The UK's National Institute for Health and Care Excellence (NICE) has issued guidelines. They recommend that lifestyle interventions should be the first treatment offered for obesity: weight management programmes [which] include behaviour change strategies… to increase people's physical activity levels or decrease inactivity, improve eating behaviour and the quality of the person's diet, and reduce energy intake.’

However, there is no guidance on whether this should be delivered to groups or to individuals. This research may be considered as part of the guideline update, due in 2023.

What’s next?

Healthcare professionals can refer people with obesity to group weight loss programmes, with the confidence that group programmes are effective. They can tell patients that groups work at least as well, if not better, than individual treatment programmes. 

However, individual preferences or circumstances mean that groups are not suitable for everyone. People with anxiety or those needing a translator, for example, may not benefit from group treatment in the same way as others. Social support in groups, and more intense intervention, may explain the greater weight loss, the researchers say. But people’s choices will need to be respected and the most appropriate approach will vary with the individual. 

The main issue in putting this research into practice may be the availability of weight loss programmes. Where NHS programmes are not available, commercial services such as Weight Watchers or Slimming World may be a good option.

It would be helpful to see research into the components of group programmes which make them better than one-to-one treatment. It could be peer support from others in the group, for example, or having more contact time with professionals (than those treated individually). 

You may be interested to read

The full paper: Abbott S, and others. Group versus one-to-one multi-component lifestyle interventions for weight management: a systematic review and meta-analysis of randomised controlled trials. Journal of Human Nutrition and Dietetics 2020;34:3

The 2014 NICE clinical guideline on obesity: Obesity: identification, assessment and management.  


Funding: The research was carried out as part of a Masters in Clinical Research Studentship funded by National Institute of Health Research (NIHR). 

Conflicts of Interest: The study authors declare no conflicts of interest.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.


Study author

People were more likely to lose 5% of their body weight in the group setting. They had the extra social support, not just from the clinician, but from others with obesity in the group. This may be why there was a difference in weight loss. At a national level, if everyone had access to groups, it would increase the number of people who lose that 5%, and that’s clinically important.

With treatments for obesity, we’ve got to be mindful that the options people have are a postcode lottery. There are areas of the UK where they might not have the option to be referred to either a group or one to one intervention. It’s not as simple as saying we should refer everyone to groups, because groups might not be available everywhere. Commercial weight loss programmes like Weight Watchers and Slimming World are rarely available free of charge through primary care, but they are available nationwide. Access to commercial slimming groups is much easier than NHS treatment.

From a clinical perspective, groups are more feasible because they can reach a lot more people in one hour than if delivered one-to-one. If we want to increase access to treatment for obesity, group interventions may be a practical and feasible way of reaching more people and importantly, this research shows that they are effective.

Sally Abbott, Assistant Professor in Dietetics, Faculty of Health and Life Sciences, Coventry University 

Member of the public

This systematic review provides the first updated evidence for over a decade on the comparative effectiveness of group versus one-to-one lifestyle interventions for weight management. For the first time, effectiveness has been assessed by the attainment of a 5% weight loss.

The review acknowledges that further research is required to understand why, where and when groups were more effective, given there were differences between the study populations: the contact hours they had, their diversity, cultural preferences, and the NHS resources available to them.

The authors say that greater social support and more intense interventions may lead to greater weight loss. For front-line staff involved in behavioural change, this study may reinforce what they already believe. Further research into the how’s and why’s of weight management is needed for service provision to become more effective.

Pamela Rees, Public Contributor, Nottingham 


The global rise in obesity and related health risks has intensified the search for effective weight loss programmes. The conclusion of this paper that group multi-component lifestyle interventions are superior to one to one interventions is an important finding.

Further research is now needed to understand the reasons why group sessions lead to more weight loss than one to one.  It will be beneficial to know if this success can be replicated online and who engages well with each method. If peer support is a factor here it would be valuable to look at how this can be enhanced and can this lead to cost savings. Internet weight loss programmes suggest that participants supporting each other via chat rooms leads to better outcomes so it is important to look at lessons learned when designing future studies.

Avril Collinson, Associate Professor and Academic Lead in Dietetics, University of Plymouth