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/m(2).
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 timing of intervention warrant further study.