The effect of autonomous and controlled motives on eating dysregulation: Implications for individuals classified as underweight, overweight or obese

Introduction Controlled and autonomous motivational factors from self-determination theory have previously been highlighted as key factors in eating regulation. The present study examined controlled motives as an overarching motivational factor in eating dysregulation and examined its effects on dieting behaviour for those who are underweight, overweight or obese. Objective To examine whether the influence of controlled motives on dieting behaviour would be moderated by body mass index (BMI). Specifically, it was hypothesised that controlled motives would be associated with high levels of dieting behaviour in underweight individuals and low levels of dieting behaviour in individuals classified as overweight or obese. Method One hundred and thirty-seven participants completed the measures of height, weight, and motivation and intentions towards watching their diet and subsequently completed a measure of dieting behaviour two weeks later. Results Moderated regression and simple slopes analyses provided support for the hypothesised effects at underweight, overweight, and obese range BMIs. Conclusion The effect of controlled motives on dieting behaviour is dependent upon BMI and therefore varies across underweight, overweight, and obese individuals. The implications of controlled motives and external pressures to watch one's diet are discussed.