We show how the biophysical nature of the shea tree affects the ethics of access to shea trees and in turn, affects the local diet in Burkina Faso. The shea tree is the most common tree in Sudanian parklands in Burkina Faso and shea butter is the main source of fat in the local diet in rural areas. We show that the globalization of shea market along with regional and local social and ecological changes in recent decades have triggered the redefinition of access to shea in western Burkina Faso. The nature of the tree, its longevity (200 years) and its management (it is natural, not planted in an agrarian system), affect the ethics of access that are currently being renegotiated. Based on qualitative data and a socio-economic survey of 280 households in three villages in western Burkina Faso, we discuss how interactions between nature and society on access to shea can alter local power relationships, and hence affect the use of shea butter in the local diet. The impact on food is two-fold: late comers, whose access to shea is tending to become more restricted, have to find a substitute for shea butter as a source of fat, and women in general may find it more difficult to buy "condiments", the ingredients for their sauces, because the income from shea is now partly controlled by the men in the household, whereas it was formerly women's income.