Central to food security interventions in Sub-Saharan Africa stands the value chain approach. The underlying idea is that connecting farmers to input and output markets and sources of knowledge and technology will enhance their food security status. In spite of positive impacts measured in especially food supply, there is scant evidence of the long-term effects on food security. For a better grasp of the impacts of a maize value chain intervention in North Ghana, we have experimented with an approach that focuses on interactions and feedback loops between the value chain and its local context. Such approach allowed us to identify dynamics that affect food security in the long run. In the case of Northern Ghana farming systems, household income and diets are increasingly dependent on maize, which increases risk of food insecurity in case of climate setbacks or market shocks. The exercise reveals how a linear value chain approach obscures the dynamic effects cascading from the intervention that may actually hamper food security in the long run. A systems approach may help to better grasp the consequences of external interventions at the local level.