Childhood obesity is a growing public health concern in many African countries. In South Africa, young children in urban low-income settings have been identified as being particularly at risk of overweight and obesity, while childhood undernutrition also persists. There is a need to develop and test context-appropriate interventions for the prevention of overweight and obesity among children in African settings. The aim of this thesis was to assess the state of the evidence related to childhood obesity prevention in Africa (Chapter 3), and South Africa specifically, and to conduct formative research to inform the development and evaluation of obesity prevention interventions (Chapters 4-7).

I first conducted a systematic review of childhood obesity prevention interventions in African countries in order to evaluate existing evidence with respect to effectiveness and implementation. Overall, I found evidence of small beneficial intervention effects on physical activity and anthropometric outcomes, but not on dietary behaviours. More interventions had been evaluated in South Africa (n=9) than any other African countries (n=5), and there was only one Tunisian intervention targeting preschool age children. This informed the narrowing of the thesis focus to preschool age children (age 3-5 years) in South Africa. Implementation findings largely centred on the challenges of resource constraints.

To further understand which behaviours to target and how, I conducted in-depth interviews with 16 caregivers of preschoolers in Soweto, which is a low-income urban setting in South Africa. I found that while parents are concerned with their children’s health and happiness, they do not necessarily consider weight to be of relevance unless it is causing noticeable health problems or attracting negative comments. I also identified barriers to healthy behaviours on different social-ecological levels, and the most promising avenues for interventions were targeting aspects of the preschool food environment and family routines, while recognising wider structural factors like unemployment. I concluded that the promotion of children’s healthy behaviours in South Africa needs to be done in a weight-inclusive and non-stigmatising way that recognises contextual factors, such as parents’ limited sense of agency in relation to children’s health and weight, safety concerns, unemployment, and resource constraints.

Finally, I conducted a qualitative process evaluation in the context of a feasibility study of a community health worker-delivered, home-based intervention to promote nurturing interactions and preschoolers’ healthy behaviours in Soweto. The focus on healthy behaviours as a way to support children’s health and development regardless of weight resonated with both participating caregivers and community health workers (CHWs) delivering the intervention. However, challenges related to the set-up of the CHW programme, such as dissatisfaction with current contracts and resulting resistance to new tasks, meant that the delivery method was not found to be feasible for behavioural interventions in this setting.

My PhD research underscores the complexity of childhood obesity and associated behaviours, particularly in a low-income setting in South Africa. I have identified potential avenues for interventions in the preschool years, and posit that these may be best delivered through community-based organisations as opposed to CHWs linked to public sector primary health care facilities.