Family food environments as determinants of preschool-aged children's eating behaviours: implications for obesity prevention policy. A review.(Statistical Data Included)

Abstract Children's eating behaviours are fundamental to their health. Dietary surveys indicate that children's food consumption is likely to promote a range of diet-related diseases, including overweight and obesity, which are associated with a range of psychosocial and physical disorders. With the prevalence of overweight and obesity rapidly increasing, opportunities for informed prevention have become a focus of strategy. Diet is recognised as important in the genesis of obesity. We present data that demonstrate that eating behaviours are likely to be established early in life and may be maintained into adulthood. We review literature that shows that children's eating behaviours are influenced by the family food environment. These findings suggest that the family environment should be considered in developing obesity prevention strategy for children, yet the current strategy focuses primarily on the school environment. Those factors in the family environment that appear to be important include: parental fo od preferences and beliefs, children's food exposure; role modelling; media exposure; and child-parent interactions around food. However, the existing data are based on small scale and unrepresentative US samples. At a population level, we have few insights regarding family food environments and consequently little information about how such environments influence children's eating behaviours and thus their risk for obesity. We suggest research that may promote a better understanding of the role of family food environments as determinants of children's eating behaviour, and consider the implications for obesity prevention in Australia. (Aust J Nutr Diet 2001;58:19-25)

Key words: eating behaviours, children's eating, family food environments, obesity prevention, paediatric obesity.

Introduction

Obesity has reached epidemic proportions throughout the world (1). In Australia, the prevalence of obesity [body mass index (BMI) [greater than] 30kg/[m.sup.2]] and overweight (BMI 25-30 kg/[m.sup.2]) is rapidly increasing (2), with most recent data showing more than half of all adults are obese or overweight (3). However, this problem is not restricted to adults. In Australia, recent estimates from three independent surveys (4) suggest that 16.1 to 16.9% of boys are overweight and 5.1 to 6.9% are obese. Figures for Australian girls are 17.4 to 20.4%, and 5.7 to 7.0% respectively. In these analyses Booth et al. used BMI as the index of adiposity, and recently published BMI cut-off values (5) were used to categorise obesity and overweight (4).

Halting the rising prevalence of overweight and obesity in children is an important public health priority (1,6). Overweight and obesity in childhood have a significant impact on psychosocial health, with overweight children often becoming targets of early and systematic discrimination (7). There are also physical health consequences (7,8). Guo and Chumlea report that the risk of obese children (defined as BMI above the 95th percentile for weight) developing adult obesity (BMI[greater than]28) is up to 80% at age 35 years (9). Obesity in childhood has been shown to be an independent risk factor for adult obesity (10) and to have implications, independent of adult obesity, for health in adult life. For example, Must et al. (11), in considering long-term morbidity and mortality of overweight adolescents, found that adolescent overweight predicted a broad range of adverse health effects that were independent of adult weight. In adults, overweight and obesity negatively impact on psychosocial and physical health (12,13).

The aim of this review is to examine the evidence of the role of family food environments as determinants of children's eating behaviours, (i.e. behaviours related to the consumption of food), and the implications for obesity prevention. We examine the role of diet in the development of obesity and present data regarding contemporary food habits of Australian children. We consider the development of children's food preferences and how these track into adulthood, and we review data regarding the relationship between food preference and dietary intake. We consider the existing literature regarding the role of the family environment in influencing children's food preferences and dietary intake. In particular we examine the influence of parental food preferences and beliefs, and contemporary food trends on children's food exposure; role modelling; media exposure; and child-parent interactions around food. Against this background we examine the strengths and weaknesses of Australian obesity prevention strategy fo r young children. We suggest directions for future research to inform the development of obesity prevention policy and facilitate the design of better targeted obesity prevention interventions for young children.

The role of diet in the development of obesity

Diet is recognised to be important in the development of obesity. However, there is debate regarding the relative importance of diet versus activity in the genesis of fatness (14,15). This debate has been heightened by the anomalous situation whereby dietary surveys in the US suggest that fat and energy consumption are reducing, while obesity prevalence is increasing (16). However, these data have been challenged by recent ecologic data that suggest that energy availability in the US increased by 15% between 1970 and 1994 and is likely to be a major contributor to increases in average body weight (17). Furthermore, our understanding of fat consumption, as reported in dietary surveys, is weak. Issues such as underreporting of fat intakes (18,19), difficulty quantifying fat contained in food prepared away from home, and, in the Australian context, an inability to meaningfully compare nutrient data from the three dietary surveys conducted this century, must be considered before we conclude that fat intakes are d eclining.

Contemporary food habits of Australian children

The most recent National Nutrition Survey (20) suggests that in many respects the diet of Australian children does not meet the current dietary guidelines. In analyses we have performed using the National Nutrition Survey confidential unit record files (3), foods that are considered to comprise the core food groups (21), such as breads and cereals, milk, meat, fruits and vegetables, were consumed regularly by the majority of five- to eight-year-olds on the day of the National Nutrition …