Rapid economic transformations have both positive and negative consequences for nutrition and health. This article presents data from an area of rural Costa Rica that has experienced a rapid economic shift from dairy farming and coffee production to a mixed economy based increasingly on tourism and to a lesser extent on agriculture. During a one-year period (2004–2005), sociodemographic, employment, dietary intake, food security, anthropometric, and ethnographic (food habits) data were collected from 148 households in two rural communities. The results show that 50 percent of the households are directly involved in the tourism industry, while many others rely on economic strategies that combine involvement in tourism with agricultural activities. Overall, high rates of food insecurity were documented (with over 70 percent of the households experiencing some level of food insecurity over the previous 12 months). The data also show high rates of caregiver and child overweight and obesity and a diet that varies according to food security status. Syndemics theory, which postulates that the dynamic interaction between co-occurring conditions magnifies the effects of each one in isolation can be used to understand how malnutrition (overnutrition) related to economic insecurity and overweight and obesity together may be contributing to the rise in chronic diet-related diseases, such as hypertension and type-2 diabetes, in the study area. The interactions between these comorbidities point to the need for the development of multidimensional public health interventions that couple individual behavior change and community-driven efforts that reduce economic insecurity and ameliorate food insecurity, resulting in more balanced diets and a reduction in overweight and obesity.