Eating behaviours like how full you feel after eating a meal or how quickly you eat have been related to the development of obesity in infants, children and adolescents. A new questionnaire to measure these behaviours is currently being developed for use with adults and could reveal new options for identifying people at risk of gaining weight and thus most in need of help to prevent weight gain. We would like to use this questionnaire in ALSPAC to measure these types of behaviours and work out if they are useful for predicting weight gain. We will also look at factors throughout life (previously measured in ALSPAC Young Adults) that are associated with adult eating behaviours. Ultimately this will enable us to design ways to help people to avoid eating in ways that makes gaining too much weight more likely.