DIAL now protocol: A randomized trial examining the provision of phone coaching to those with sub-optimal early...

While low-intensity Internet-delivered weight loss (IDWL) programs are efficacious, many patients fail to achieve clinically significant weight loss (WL). Given the positive association between 4-week and post-treatment WL, providing a more intensive intervention for those with sub-optimal 4-week WL may improve outcomes for a greater proportion of individuals. This stepped-care approach would minimize cost by reserving more aggressive treatment for those with sub-optimal early WL.

This randomized trial examines whether the provision of brief or extended phone coaching for those with sub-optimal early WL improves 4- and 12-month WL when compared to no coaching. Secondary aims include examination of cost/kg WL and intervention engagement.

450 individuals (age 18-70 years, BMI: 25-45 kg/m²) will be randomized to: 1) IDWL+3 weeks of coaching ('Brief'), 2) IDWL+12 weeks of coaching ('Extended'), or 3) IDWL only ('Control'). All individuals will receive a 4-month IDWL program followed by an 8-month IDWL maintenance program. At week 4, individuals will be classified as early sub-optimal responders (<4% WL) or initial responders (≥4% WL). Individuals with sub-optimal early WL randomized to 'Brief' or 'Extended' will receive 3 and 12 weeks of phone coaching respectively, starting at week 5. Those with sub-optimal early WL randomized to 'Control', and initial responders will not receive any coaching. Assessments will occur at 4 and 12 months.

Study findings can inform the development of more effective IDWL programs. This model which provides additional support to those with sub-optimal early WL can easily be translated into healthcare and community settings.