Over the past three decades, agrarian reform areas have transformed urban and rural spaces across Brazil. Although these areas’ creation reduced inequalities and environmental problems, their residents still experience several constraints and vulnerabilities associated with water, energy, and food provision. Drawing on the water-energy-food (WEF) nexus’ critical and territorial perspectives, this paper aims to better understand the agrarian reform areas’ challenges in peri-urban interfaces towards social justice. We analyse a territory in the Northeast portion of the São Paulo State, where it is located the Sepé Tiaraju agrarian reform settlement in interface with two municipalities. We suggest that agrarian reform areas can activate a progressive and concrete environmental change at the local level where food is the key element to redefining the area’s nexus. However, socio-political and spatial dynamics involving water and energy for the sugarcane sector, the municipal government, and tense relationships among residents around food also reproduce unequal access to resources. This paper contributes to the emerging critical literature and its efforts to politicize the nexus debate, giving more nuanced views to the complex and contradictory dynamics involving environmental problems and social justice struggles.