Behavioural nutrition and physical activity in young people : the role of the family

The increasing evidence of associations between inactivity and poor diets in young people and both immediate and long term health implications is of public health concern. There is a need to further understanding of young people's health behaviours, to facilitate the development of behaviour change strategies promoting healthy behaviours. This thesis, provides seven studies focusing on the family environment and the influences that the family and parents have on young people's physical activity and dietary behaviours. Chapter 2.1 describes a systematic review of family correlates of fruit and vegetable consumption in children and adolescents. Chapter 2.2 describes a systematic review of family correlates of breakfast consumption among children and adolescents. Systematic reviews are an essential component of evidence-based practice, and both reviews were conducted to examine the state of the current literature examining family environmental influences on aspects of young people's dietary behaviours. In the context of this thesis, these systematic reviews are of primary importance as they were instrumental in shaping and informing the direction of the research described in later chapters. Chapter 3 broadens the investigation of young people's health behaviours and describes two cross-sectional studies examining both physical activity and dietary behaviours. Chapter 3.1 describes a study examining patterns of adolescent physical activity and dietary behaviours. This study describes how adolescents are at risk of not meeting the recommendations for multiple health behaviours (e.g. physical activity, fruit and vegetable consumption, and breakfast consumption). Chapter 3.2 was designed to fill several gaps in the literature about the correlates of multiple health behaviours and also to gain a greater insight into the transferability of parental behaviours to different health behaviours in children. Chapter 3.2 describes a study examining family influences on young peoples fruit and vegetable consumption and physical activity, and on combinations of these behaviours (e.g. high physical activity and low fruit and vegetable consumption). Chapter 4.1 was designed to fill gaps in the literature by examining the association between family circumstance (parental marital status, maternal education, maternal employment status, number of brothers and number of sisters) and adolescent dietary behaviour, and 2-year change in dietary behaviour. Chapter 4.2 was designed to fill gaps in the literature by examining the relationship between parenting styles, family structure and aspects of adolescent dietary behaviour. Together, the six studies described above established a rationale and informed the content of the pilot family-based intervention described in Chapter 5. This thesis found that particular aspects of the family environment and particular attributes of parenting were associated with positive physical activity and dietary behaviours of young people. Such findings add considerably to the existing literature and are important as they suggest that even as young people age, the family environment and the emotional context within which parent-child interactions occur are vital for positive health behaviours. Targeting such facets of the family and parenting holds great potential for behaviour change strategies.