ETIOLOGY OF EATING AND PHYSICAL ACTIVITY BEHAVIORS
Why is this topic significant?
To develop approaches to treatment and prevention, it is important to have some understanding of the etiology of obesity and the factors involved in the development of eating and physical activity habits. This understanding is particularly relevant to the growing problem of childhood obesity.
The prevalence of childhood over-weight has increased dramatically over the past 2 decades, nearly doubling by some estimates (56,57). Childhood overweight is particularly common in minority groups, such as African-Americans and Hispanics. With this increased prevalence of childhood obesity has come a startling increase in the prevalence of type 2 diabetes in children and adolescents (2).
Childhood obesity is also significant because of its psychosocial costs (58,59). In a recent study (59), overweight adolescent females, followed for 7 years, were found to complete less schooling, to be less likely to get married, and have lower income than their normal-weight peers.
Obesity in childhood often continues into adulthood. However, the more common path to obesity in adulthood is to be normal weight as a child and gradually gain weight during adulthood (60). Highrisk periods for weight gain include the time period of 25-34 years of age and the time periods surrounding menopause (61). Pregnancy can also be a high-risk time period for a subset of women (62).
Although weight gain and obesity are clearly due to problems in energy balance, it is still unclear whether this is due to high dietary intake, a low level of physical activity, or both. Secular changes in dietary patterns (e.g., increased reliance on fast foods and increased portion sizes) and physical activity (e.g., decreased playtime and increased use of television as a child-care strategy) may contribute to these changes. A better understanding of the process by which children establish their eating and physical activity preferences and the changes that occur with age will facilitate development of more effective approaches for prevention and treatment of obesity.