Enhancing the Sustainability of Weight Loss and Healthy Diet Through Mobile Phone-enabled Social Interactions

Over the past two decades a very simple, low-cost and consistently effective intervention has been developed that we believe has potential to be disseminated online in primary care. The intervention, "action planning" (AP), is also known as "if-then planning" or "implementation intentions". Action Planning is one element of the process of self-regulation (Wing et al 2006; Luszczynska et al 2007), in which individuals identify (1) situations that challenge their ability to perform a behavior and (2) make a specific plan for what they will do when the situation is next encountered. Luszczynska and colleagues observed that adding a single session of action planning onto a portion-controlled meal intervention increased the weight lost from 2.1 kg to 4.2 kg (Luszczynska et al 2007). A meta-analysis of 94 studies using AP, nearly all of which included a single-dose, observed a mean effect size of Cohen's d=.65, consistent with a medium to large effect. Studies of repeated doses appear to have even greater effects (Chapman and Armitage 2010). Dr. Sciamanna recently completed a pilot feasibility study in which 53 subjects used an AP intervention for weight loss for 2 months. All subjects attended a 1-hour introductory session about the use of portion-controlled meals and pedometers. Subjects were then emailed one AP writing prompt each day, representing one of the 21 of the most common barriers to weight control (Bond et al 2001). Despite receiving no personalized feedback, over 2 months the subjects wrote action plans, on an average of 4.2 days per week. After 2 months, the average weight loss was 7.7 pounds. These adherence levels, though short-term, are greater than typical web-based weight control interventions included in a recent Cochrane review (Wieland 2012). This pilot study suggests that this low-cost intervention approach may have unusual levels of fidelity. Even though the average activities of user engagement with AP is quite high in the first two months, there is a slight decline toward the third month. In focus group discussions after a pilot conducted by Dr. Sciamanna in the Philadelphia area, participants of the pilot indicated consistent difficulties in coming up with ideas for habits that might be useful. These observations motivates this proposed study.