Proponents of large-scale land investments (LSLI) still promote them as a development opportunity, which can lead, among other benefits, to job creation and enhanced food security for local communities. However, there is increasing evidence that these investments often deprive affected communities of their access to land, with multiple negative impacts on livelihoods, food security and on the environment. This paper relies on empirical data to present an analysis of LSLI and food (in)security – crucially at the level of individuals in two villages in the Ruvuma region, Tanzania, over 10 years after the acquisition of village land within the Southern African Growth Corridor of Tanzania (SAGCOT). We introduce an innovative framework that permits an integration of a rights-based approach with the Sustainable Livelihoods Framework to explore smallholders’ livelihoods and experiences of food insecurity. Our paper demonstrates how this integration, along with attention we have given to the FAO’s PANTHER principles, adds the missing yet crucial dimension of accountability on the part of national governments as duty bearers. Our findings show that in the case of these two villages, the human rights principles of participation, accountability, transparency and empowerment are severely undermined, with women bearing the brunt in all these domains. This overall state of affairs is, we argue, due to inadequate monitoring and evaluation of LSLI processes themselves and low levels of commitment on the part of institutions in Tanzania to monitor the promises made by investors. This in turn demonstrates an accountability deficit on the part of duty-bearers within LSLIs, and limited capacity of affected community members to claim their rights. Individual food insecurity experience in the two communities correlates, among other characteristics, with lack of land ownership, employment and income-generating activities. The rights-based livelihoods framework applied in this study points to serious deficiencies in the LSLI model as presently endorsed in SAGCOT, and emphasises the fact that access to land in Tanzania is a precondition for the realisation of the right to adequate food and thus a critical requirement for achieving and maintaining food and nutrition security. We conclude by arguing that progressive coalitions within and beyond national states must devise policies and institutions that empower individuals and civil society actors to make demands on their governments to respect, protect and fulfil their obligations regarding the legally enforceable right to food.