This demonstration and evaluation project will test the effectiveness of a family-based health behavior change intervention. The aim is to assist family members to initiate and maintain dietary and physical activity behaviors which are believed to be linked to risk factors for cardiovascular disease: decreasing the consumption of foods high in sodium and saturated fats and increasing the amount of aerobic activity (60-80% of capacity). The family is a major environment within which health behaviors are developed and prior studies, including a pilot study by the P.I., suggest that family-based interventions are feasible and have the potential for enhancing maintenance of behavior changes. San Diego elementary schools will be randomly assigned to either the experimental or control condition. Anglo and Hispanic-American families with a fifth or sixth grade child will then be recruited for participation. The intervention which is based on social learning theory, will utilize in vivo practice and family modeling and support to impart the motivation and skills required to make long-lasting health behavior changes. Ethnically-homogeneous groups of families will meet at the schools for 12 weekly intensive sessions and six maintenance sessions spaced throughout the following nine months. Outcome measures are taken at baseline, after the intensive intervention (3 mos.), after the maintenance sessions (12 months), and one year after the maintenance sessions (24 months). Primary measures are the self-reported sodium and saturated fat intake and physical activity. These measures are supplemented by direct observation of behavior, a submaximal graded exercise test, resting blood pressure, body mass, urinary Na/K ratio, and serum cholesterol and lipoproteins. In addition, measures of family process acculturation, social support and self-efficacy will be collected in order to study the process of health behavior change in families and to detect ethnic differences in these processes. Experts in the fields of epidemiology, pediatrics, health education, psychology, nutrition, exercise physiology and biostatistics have collaborated to design the intervention and evaluation. Close cooperation of the San Diego Unified School District ensures access to a sufficient number of families of fifth and sixth grade children.