title: Mechanisms of change in diet and activity in the Make Better Choices 1 trial.
abstract: OBJECTIVE
  The Make Better Choices 1 trial demonstrated that participants with unhealthy diet and activity behaviors who were randomized to increase fruits/vegetables and decrease sedentary leisure achieved greater diet and activity improvement than those randomized to change other pairs of eating and activity behaviors. Participants randomized to decrease saturated fat and increase physical activity achieved the least diet-activity improvement. This study examined which psychological mechanisms mediated the effects of the study treatments on healthy behavior change.
  
  
  METHODS
  Participants (n = 204) were randomized to 1 of 4 treatments: increase fruits/vegetables and physical activity; decrease saturated fat and sedentary leisure; decrease saturated fat and increase physical activity; increase fruits/vegetables and decrease sedentary leisure. Treatments provided 3 weeks of remote coaching supported by mobile decision support technology and financial incentives. Mediational analyses were performed to examine whether changes in positive and negative affect, and self-efficacy, stages of readiness to change, liking, craving and attentional bias for fruit/vegetable intake, saturated fat intake, physical activity, and sedentary leisure explained the impact of the treatments on diet-activity improvement.
  
  
  RESULTS
  Greater diet-activity improvement in those randomized to increase fruits/vegetables and decrease sedentary leisure was mediated by increased self-efficacy (indirect effect estimate = 0.04; 95% bias corrected CI, 0.003-0.11). All treatments improved craving, stage of change and positive affect.
  
  
  CONCLUSIONS
  Accomplishing healthy lifestyle changes for 3 weeks improves positive affect, increases cravings for healthy foods and activities, and enhances readiness to make healthy behavior changes. Maximal diet and activity improvement occurs when interventions enhance self-efficacy to make multiple healthy behavior changes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
authors.affiliation: Department of Preventive & Behavioral Medicine, University of Massachusetts Medical School.
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Schneider
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Coons
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: H Gene
authors.initials: HG
authors.lastname: McFadden
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Pellegrini
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: Andrew
authors.initials: A
authors.lastname: DeMott
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: Juned
authors.initials: J
authors.lastname: Siddique
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois.
authors.forename: Donald
authors.initials: D
authors.lastname: Hedeker
authors.affiliation: Department of Psychology, Wittenberg University.
authors.forename: Laura
authors.initials: L
authors.lastname: Aylward
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine.
authors.forename: Bonnie
authors.identifier: 0000-0003-0692-9868
authors.initials: B
authors.lastname: Spring