The NHS Low-Calorie Diet Digital Programme: Fidelity of behaviour change technique delivery

Aims
NHS England commissioned independent service providers to deliver the NHS Low-Calorie Diet Programme pilot. Previous research has illustrated a drift in the fidelity of behaviour change techniques (BCTs) during the delivery of the programme provided through face-to-face group or one-to-one behavioural support. The aim of this study was to assess the delivery fidelity of the BCT content in the digital delivery of the programme.

Methods
Online, app chat and phone call support content was coded using The Behaviour Change Technique Taxonomy. BCTs delivered by each service provider (N = 2) were calculated and compared to the BCTs specified in the NHS service specification and those specified in the providers' programme plans.

Results
Between 78% and 83% of the BCTs identified in the NHS service specification were delivered by the service providers. The fidelity of BCT delivery to those specified in providers' programme plans was 60%–65% for provider A, and 82% for provider B.

Conclusions
The BCT content of the digital model used in the NHS-LCD programme adhered well to the NHS service specification and providers' plans. It surpassed what has been previously observed in face-to-face services provided through group or one-on-one behavioural support models.