In pursuit of control and happiness: the psychological way to a lower body mass index, but hold the dieting!

Background: Obesity continues to present a major public health concern (NHS, 2008). This study aimed to explore the relationship between body mass index (BMI) and the affective states: happiness, anxiety and depression, alongside self efficacy and eating behaviours. It further aimed to identify if these components influence overeating behaviour, a factor that is empirically linked to a high BMI (Macht, 2008). Method: Data was collected from 104 adults (76% female), mean age 38.48 (SD = 12.47) years, who completed questionnaires which measured happiness, depression, anxiety, generalised self efficacy, dietary restraint, emotional eating and binge eating. Height and weight were also taken to calculate BMI, which ranged from 16.41-44.38 with a mean BMI of 26.92 (SD = 5.98). Results: Findings confirm that there are significant relationships between personal control, affective states, eating behaviours and BMI. Generalised self efficacy and happiness were revealed as predominant psychological factors, correlating with all variables (p < .001). Controlling for age and gender, generalised self efficacy explained the variance in emotional eating by 16%, binge eating by 12% and BMI by 19%. Dietary restraint accounted for 66% of the variance in binge eating behaviour and was also the highest predictor of BMI (R2 = .45), with depression explaining a further 9%. Finally, investigating the influence of emotional eating, negative affect (R2 = .32) and dietary restraint (R2 = .07) were revealed to be the most significant predictors. Conclusion: Evidence presented here highlights the importance for behavioural medicine to consider the influence of self efficacy and affect when tailoring weight loss interventions, while also exercising caution over the negative influence of dieting behaviour.