Objective: To investigate the efficacy of motivational interviewing (MI) to elicit change in eating and physical activity behaviors in women with overweight and obesity before conception.

Design: A randomized controlled trial was conducted. The participants were randomly divided into intervention and comparison groups. Data were gathered using the Three-Factor Eating Questionnaire Revised 18-item version (TFEQ-R18), International Physical Activity Questionnaire (IPAQ), and Stages of Change checklist.

Setting: Primary health centers of Tabriz, Iran.

Participants: The participants were 70 women with overweight or obesity, aged 18-35 years, who were referred for preconception care.

Intervention(s): The intervention group received 6 MI sessions, and the comparison group received routine preconception care.

Main outcome measure(s): Variables of primary outcomes were eating behavior measures and physical activity levels 8 weeks after intervention.

Analysis: Independent t test, ANCOVA, Fisher exact test, Mann-Whitney U test, and Wilcoxon test were used.

Results: The MI had a positive effect on physical activity in the moderate and vigorous levels in the intervention group (P = .01, P = .02, respectively). After the intervention, the mean score of cognitive restraint in the intervention group was higher than in the comparison group (adjusted mean difference, 16.9; 95% CI, 10.8 to 23.0; P < .001), whereas there were no significant differences between the 2 groups in terms of emotional and uncontrolled eating (P = .33 and P = .25, respectively).

Conclusions and implications: The MI had a positive effect on physical activity and eating behavior change, except for uncontrolled and emotional eating. Future studies to examine differences between overweight and women with obesity and within other populations is warranted.

Keywords: eating behavior; motivational interviewing; obesity; physical activity; preconception.