Long-term effect of motivational interviewing on dietary intake and weight loss in Iranian obese/overweight women.

Background: This study aimed to determine whether motivational interviewing (MI) could change dietary habit and body mass index (BMI) in obese/overweight women.

Methods: A cluster-randomized controlled study was performed in four health centers in Qazvin, central Iran. In total, 327 obese/overweight women were selected by a multi-stage sampling method and randomly assigned into control and experimental groups. Food frequency (using questionnaire; FFQ), BMI, and metabolic markers including blood pressure, total serum cholesterol and fasting blood glucose levels were measured in all participants. Data were collected twice (before and one year after the MI interventions). Data were analyzed using student t-test, and Stepwise Linear Regression.

Results: There was a significant increase in daily consumption of dietary fiber, whole grain products, fruits and vegetables in the MI group (P<0.05). The consumption of meat product, total fat, saturated fat, carbohydrate and total energy intake were also significantly reduced after MI intervention (P<0.05). As a result, body weight and BMI were significantly reduced in the intervention group compared to the control group (P<0.05).

Conclusion: MI is suggested to be an effective strategy to change life style and reduce BMI in overweight/obese women in the long term. This effect needs to be further investigated in different gender and age populations.