Personal and family determinants of dietary behaviour in adolescents and their parents

The first aim of the present study was to investigate the contribution of personal and family determinants in explaining variance in dietary behaviour using objective as well as subjective food scores as dependent variables. The second aim was to provide insight into the aggregation of determinants of dietary behaviour within families. 104 family dyads (n = 208) consisting of an adolescent and his/her parent were recruited. All participants went through a computer routine and completed questionnaires to investigate personal determinants, family interactions around food and more general family characteristics. Results revealed that family determinants explained a maximum of 10% additional variance in dietary behaviour over and above personal determinants. Further, considerably more variance in subjective food scores could be explained (R-2 mainly between .35 and .65) when compared to variance in objective food scores (R-2 mainly between .10 and .40). Finally, the family aggregation was rather low. This argues against the hypothesis of a strong family base of the traditionally used personal determinants. It also shows that a subject's reports of family interactions are mainly a reflection of an individual's perception and can hardly be considered to be objective truth.