American Heart Association

American Heart Association

December 03, 2015
4 min read

Mobile intervention yielded significant, sustained improvements in diet, activity levels

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ORLANDO, Fla. — A mobile app-based intervention resulted in significant and sustained increases in fruit and vegetable intake and decreases in saturated fat intake and sedentary leisure time, according to results of the MBC2 trial reported at the American Heart Association Scientific Sessions.

The study followed results from the MBC1 trial, in which 204 adults were incentivized to increase their fruit and vegetable intake, reduce their saturated fat intake, increase physical activity and reduce sedentary leisure time. Participants received $175 for reaching 50% of their goal within 1 week, then reaching and maintaining their goals for 2 weeks. Participants in MBC1 were “incredibly successful,” and maintained approximately half of the improvement that occurred with the financial incentive even after they stopped receiving payment, Bonnie Spring, PhD, director of the Center for Behavior and Health at Northwestern University Feinberg School of Medicine, said during a presentation. Spring also noted that when participants targeted improvements in fruit and vegetable intake and sedentary time, they also improved their saturated fat intake; however, physical activity levels did not improve without specific targeting.

The goal of the MBC2 trial, Spring said, was to determine whether sustained and substantial behavioral changes could be obtained without sizable financial incentives, and whether improvement to physical activity levels could be added as a goal without negatively influencing improvements to other risk behaviors.

MBC2 included 212 adults (mean age, 40 years; 75% female) with four CVD risk behaviors as indicated by self-report: low intake of fruits and vegetables; sedentary screen time of more than 2 hours a day; high saturated fat intake; and low levels of moderate-vigorous physical activity. Participants were randomly assigned to one of three treatment approaches: increasing fruit/vegetable intake and reducing sedentary time initially, followed by attempting to increase physical activity levels (sequential approach); targeting physical activity, fruit/vegetable intake and sedentary leisure time (simultaneous approach); or addressing stress and sleep behaviors alone (control).

Participants provided data on their diet and activity levels using a smartphone app. During a 12-week initiation phase, they received weekly calls from a coach to provide lesson plans and personalized feedback. During the subsequent maintenance phase, participants received calls from their coach every other week for 3 months and then monthly through 9 months. The financial incentive was $5 for each week during the initiation phase that a participant met the goals for all four behaviors; however, no participants ever met this criteria during the course of the study, Spring said.

The primary outcome was change to diet and activity level at 6 and 9 months.

At 9 months, researchers observed significant improvements to daily intake of fruits and vegetables (mean difference, 5.9 servings), sedentary leisure time (mean difference, 126.9 minutes) and saturated fat intake (mean reduction, 3.7%) among patients in the treated groups. Spring and colleagues also observed a significant increase to the amount of daily moderate-vigorous activity in both intervention groups (mean difference, 15.8 minutes), but this did not persist to 9 months.

The differences between patients in treatment groups and controls with regard to improvements to diet and activity levels were significant at 3, 6 and 9 months, Spring said. The researchers also observed a significantly greater improvement in the sequential group compared with the simultaneous group at 6 months, but this difference was small and did not persist at 9 months, she added.

“The implication is that it’s far more possible than I would have believed to produce sustained, large-magnitude improvements in CV risk behaviors without using large financial incentives, by using technology support and a scalable approach to coaching that involves telephone coaching at a weekly interval for about 3 months,” Spring concluded.  – by Adam Taliercio


Spring B, et al. Late-Breaking Clinical Trials 2. Presented at: American Heart Association Scientific Sessions; Nov. 7-11, 2015; Orlando, Fla.

Disclosure: The researchers report no relevant financial disclosures.