Physical activity and dietary practices are well-documented in the etiology of cardiovascular diseases (CVD). While it is suspected that the behavioral roots of obesity, hypertension, hyperlipidemia, and clinical CVD are present in childhood, there have been relatively few attempts to study the early development of dietary and physical activity behaviors. Several studies of this problem are currently beginning, but the proposed project will add significantly to the growing knowledge base because half of the sample will consist of Hispanic children, and all the subjects will be from low income families. Since high levels of risk are concentrated in low income populations, it is especially important to study the early precursors of disease in this group. The proposed project will study the determinants of dietary and physical activity behaviors in 300 3 and 4 year old Hispanic and Anglo children from low income homes. The primary aims of the 5-year prospective observational study are as follows: (a) to describe the development and degree of tracking (relative stability over time) of physical activity and dietary intake of saturated fat, sodium, and calories in preschool children over a 4 year period; (b) to identify important determinants of physical activity and dietary habits in young children, with an emphasis on family determinants; (c) to describe the development and determinants of salt taste preference in young children; and (d) to determine relationships between dietary and physical activity habits in young children and physiological indicators of risk, such as blood pressure, body fat, and body mass. The preschoolers and their families will be measured every 6 months for 4 years. Children will be observed during free play periods and meals during school visits and evening home visits. Determinants were selected based on social learning theory, and include sociodemographic variables (e.g., ethnic group, education, acculturation of Hispanics); parental risk status; parental modeling, prompts and knowledge; teacher and peer prompts, salt taste preference of parents and children; child variables (e.g., ponderosity, dietary and physical activity knowledge and preferences); television influences; and opportunities for physical activity and food choice (e.g., physical availability of foods in the home, physical activity facilities). The growth curve model will be used in the analysis of data. Results of the study will add significantly to the data base on lower income Mexican American and Anglo preschool children. Such data can guide priorities for intervention among this high risk group.