Slimming World continually invests in research and development into our programme to ensure we provide the best support for our members, evaluate the effectiveness of our programme, and ensure our approach remains fully in line with national guidance.
Our latest service evaluation explored the accessibility and support that Slimming World provides to young adults. Members aged between 18-34 who had been attending Slimming World either at a community group or online for more than four weeks were asked to participate in an online survey.
Among the 3,466 respondents mean baseline BMI was 37.9 kg/m2 with a weight change of -12.4kg (-11.4%) at the time of the survey (median attendance = 32 weeks).
The evaluation also highlighted respondents:
- gained confidence in changing their eating habits (91%)
- felt able to challenge negative thoughts about their ability to lose weight (77%)
- agreed Slimming World helped them develop a better relationship with food (89%)
- changed the way they think and feel about food in a positive way (87%)
- felt supported in changing their mindset about physical activity (80%)
- were more active since accessing Slimming World’s support (64%).
There was also a significant shift in confidence to prepare healthier meals, as 96% reported they now felt confident to cook a meal from scratch and 75% are doing so more often.
In terms of alcohol consumption, 27% of members had reduced the alcohol they drink, 17% had swapped some or all for low-alcohol alternatives, 14% had cut down on binge drinking and 10% had completely stopped drinking alcohol.
Respondents also reported that their mental wellbeing had improved (58%), with the majority (85%) attributing this to the support they received from Slimming World.
In conclusion, the evaluation data suggests Slimming World supports young adult members’ confidence in their ability to manage their weight, encourages positive behavioural changes with additional health benefits linked to clinically significant weight loss.
Highlights of some of Slimming World’s extensive evidence base can be found here. For a comprehensive summary of all Slimming World-related evidence, you can view our full research portfolio or download a PDF version.
References
Ayman, A., Holloway, L., Toon, J., Avery, A., Donovan, J., Pallister, C. (2025). Supporting young adults (18-34 years) to manage their weight and wellbeing. International Journal of Obesity 49:15. Presented at UK Congress on Obesity (Sept 2025) and British Dietetic Association (December 2025)