The Drop It at Last study: Six-month results of a phone-based weight loss trial

Purpose: To address the translational research question regarding the optimal intervention "dose" to produce the most cost-effective rate of weight loss, we conducted the Drop It At Last (DIAL) study. Design: DIAL is a 6-month pilot randomized trial to examine the efficacy of phone-based weight loss programs with varying levels of treatment contact (10 vs. 20 sessions) in comparison to self-directed treatment. Setting: Participants were recruited from the community via mailings and advertisement. Subjects: Participants were 63 adults with a body mass index between 30 and 39 kg/m². Intervention: Participants received a standard set of print materials and were randomized to either: (1) self-directed treatment; (2) 10 phone coaching sessions; or (3) 20 phone coaching sessions. Measures: Measured height, weight, and psychosocial and weight-related self-monitoring measures were collected at baseline and follow-up. Analysis: General linear models were used to examine 6-month treatment group differences in weight loss and in psychosocial and behavioral measures. Results: Weight losses were-2.3,-3.2, and-4.9 kg in the self-directed, 10-session, and 20-session groups, respectively (p <.21). Participants who completed 10 or more sessions lost more weight (-5.1 kg) compared to those completed four or fewer sessions (-.3 kg, p <.04). Conclusion: Phone-based weight loss program participation is associated with modest weight loss. The optimal dose and liming of intervention warrant further study.