This study explored the relationship between BMI, external, emotional, restrained eating and dieting self-efficacy in adult males and females. An online survey using Dutch Eating Behaviour Questionnaire and scenario based Diet Self-efficacy assessed 116 females and 50 male participants over 18yrs. Emotional eating significantly predicted BMI and restrained eating. Females reported significantly higher levels of restrained and emotional eating and lower dieting self-efficacy while experiencing negative affect compared to males. Restrained eating was significantly higher for overweight compared to normal weight men. Restrained eating significantly predicted BMI in men. Dieting self-efficacy did not differ significantly between overweight and normal weight participants. A major risk factor identified for females was emotional eating and for men was restrained eating, both of which significantly contributed to weight gain. Interventions should target emotional eating and be gender specific.