Surgery remains the most effective and cost-effective long-term approach to reducing weight for adults who are severely obese, according to new research from the University of Aberdeen.

However, the study also found that high quality weight management programmes (WMPs) are effective tools in reducing weight for up to 10 years in some cases.

The study was funded by the National Institute for Health Research (NIHR). The study, which also included researchers from the University of Oxford and the UK Health Forum, reviewed 236 studies looking at evidence for acceptability, effectiveness and value for money of surgery, diet and exercise weight management programmes, and the drug orlistat.

The review found that surgery for obesity had the best long-term weight-loss results and could be a good use of NHS resources, compared with no surgery or weight management programmes on their own.

Of non-surgical approaches, very low-calorie diets produced the best weight-loss result at 12 months, but it was unclear if weight-loss was any greater than standard WMPs for longer than this.

Adding a very to an existing weight management programme was shown to not be a good use of NHS resources. However, most weight management programmes, including those with very low calorie diets, appeared to be a good use of NHS resources compared with doing nothing at all.

Low-carbohydrate Atkins-type diets, higher protein intakes or the use of meal replacements had small added effects on improving weight loss compared to other WMPs at 12 months We found no evidence that they were better than other diets after 12 months.

The best result for long-term non-surgical weight loss (over nearly 10 years) came from an intensive WMP with all of the following—a low-fat reducing , a calorie goal of 1200–1800 kcal/day, initial meal replacements or meal plans, a tailored exercise programme, , intensive group and individual support, and follow-up by telephone or e-mail. However, this type of WMP would be more costly for the NHS than simpler WMPs.

Other components of effective interventions included increasing physical activity to help prevent long-term weight regain and receiving longer-term help with diets or using the drug orlistat. Adding telephone or internet support, and group support, also helped to keep weight off.

Participants in weight management programmes valued novelty, weight management programmes endorsed by health-care providers and belonging to a group of people who shared similar issues.

Lead author Professor Alison Avenell from the University of Aberdeen said: "The purpose of this study was to examine the available evidence looking at the effectiveness and cost-effectiveness of different weight management procedures from the perspective of the NHS.

"Whilst the study shows that surgical interventions remain much more effective, provision of surgery for obesity management by the NHS is presently very low. Other weight programmes can be effective in terms of helping people who are severely obese lose and are cost-effective for the NHS."