A study to determine the effectiveness of two weight loss maintenance interventions in Counterweight Plus, a structured weight management programme.

Introduction: Long-term maintenance of non-surgical weight loss remains the most significant problem in obesity treatment. This study will compare the effectiveness of two different weight loss maintenance strategies used as part of the Counterweight Plus weight management programme. This study will also evaluate the behavioural impact of the Counterweight Plus interventions and include process evaluations and cost analysis.

Methods: 80 patients and 10 practitioners will be recruited into the study. Main inclusion criteria for patients are:

Completed Counterweight Plus, which includes 12-20 weeks total diet replacement (TDR), 8 weeks food reintroduction (FR) and achieved >10kg weight loss. All participants will be followed up for 18 months in total.

Results: The primary outcome of this study is the difference in weight change between the two groups at 6 months. Frequency of use of behavioural strategy will be quantified for both practitioners and patients during voice recorded consultations. The relationship between weight change and the use of behavioural strategy will be assessed.

Hypothesis: This study will establish if the novel intermittent use of formula diet strategy is more effective at preventing weight regain in comparison to usual care. It will also provide evidence of the frequency of use of behavioural strategies within routine Counterweight Plus delivery, as well as establishing the cost of the intervention.

Inclusion Criteria:

• Completed Counterweight Plus Total Diet Replacement and Food Reintroduction stages and achieved >10kg weight loss

Exclusion Criteria:

• People currently participating in another clinical research trial (not including BEYOND Weight Loss study)