Instrumental social support, or aid in the form of labor or money, may exert a positive influence on economic welfare and food security. Several investigators have found a positive relationship between social support and nutritional status, while others have found a negative association between social support and central adiposity. In the rural Andes, extra-household economic cooperation has long been an important adaptive strategy, and the breakdown of these relationships is one reason for high rates of rural-to-urban migration, including to the Bolivian city of El Alto. This research investigates the influence of instrumental support on women's body composition. Information was collected on individual perception of instrumental support and anthropometric indicators of nutritional status including percent body fat (bioelectrical impedance analysis (BIA)), BMI, and distribution of fat on trunk relative to limbs (Ratio of subscapular to triceps skinfold (STR)), and multiple linear regression analysis used to test the prediction that instrumental social support is positively related to body fat stores. Controlling for age and household socioeconomic status, perceived access to one or more sources of instrumental support was positively and significantly related to overall levels of adiposity. There is no evidence that STR mediates the relationship between instrumental social support and body composition. This analysis offers support for the prediction that economic social support has direct effects on women's energy stores. The interpretation of these results is somewhat ambiguous given the high levels of overweight and obesity in this population. Am J Phys Anthropol 152:51–57, 2013. © 2013 Wiley Periodicals, Inc.