A Glasgow University study found a postcode lottery in behavioural weight management interventions (BWMIs) exists across the UK.
The programmes are the first-line treatment for overweight and obese patients and routinely include actions such as restricting calories and increasing physical activity.
However, researchers who mapped services across the UK found a wide variation in how patients are being referred, the criteria they have to meet, the format, length and cost of the programmes.
The success of initiatives was also assessed and reported on in different ways, making it difficult to carry out comparisons.
Recommendations on how to consistently assess and report on obesity programmes have now been fed into guidance by Public Health England and NHS Health Scotland.
Lead author of the study Dr Jennifer Logue said understanding what initiatives work best was key to securing prolonged funding and to achieve the best patient care:
“By having the information on how each programme works we can start to better understand what works best for patients.
“This will lead to improved outcomes for all services, potential cost savings and a move towards less variation in what is delivered.”
Dr Logue, who has since moved to Lancaster University, said the lack of evidence on what works best has led to a reluctance to fund programmes.
She added: “By applying a consistent pattern of evaluation to all obesity and overweight programmes, hopefully, we will be able to prove just how effective many of these initiatives can be.”
The study has been published in the journal Obesity Reviews.