The Capability Approach argues individual advantage should be evaluated in the space of freedom of choice, that is in the space of capability. Yet, empirical applications are hampered by the lack of appropriate data and indicators. This paper aims at providing a reliable and valid indicator measuring deprivation of capability as lack of relative autonomy. Furthermore, it explores its usefulness through an ad hoc case study. Thus, it analyzes the role of women's relative autonomy for the underweight of infants and young children in a rural patriarchal community of India. Inspired by the extended model of care presented in Engle, Menon and Haddad (1999), we estimate regression coefficients in the model by Ordinary Least Square on a probabilistic random sample purposely collected. Results point out autonomy in mobility in a patriarchal society is negatively associated with the nutritional status of children. The norm-based economic framework suggests focusing on 'external capabilities' at the community level for policy interventions aimed at increasing freedom of choice of present and future generations.