Relationships involving maize (Zea mays) production, maize retained for household consumption, household maize requirement, household size, rainfall and temperatures were assessed in order to explain food insufficiency among smallholder farmers in Choma, Zambia. Post-harvest agricultural data for 1976 to 2014 were collected from the Central Statistics Office while a survey of 319 smallholder farmers and eight key informants provided data on mean annual household maize requirements and crop preference. Despite maize production in Choma increasing at an annual rate of 230.8 t/year, maize insufficiency persisted as maize retained for household consumption could not sustain the 185.2 kg per capita maize requirement by farmers in the area. While extending the maize area planted was responsible for increasing annual maize production by 1.8 t for each additional ha planted, Choma’s annual percentage population increase was larger at 2.6%, requiring an increase of 821 t/year for maize sufficiency. Maize produced was usually enough for annual consumption before sales. However, farmers sold about 50% of what they produced making the amount of maize retained for household consumption insufficient. Government incentives attached to maize production and marketing encouraged a maize-centric farming culture among farmers. Maize which had a guaranteed market from the Zambia Food Reserve Agency was allocated 73.4% of the available land over the study period. The maize centric system has encouraged mono-cropping of maize. Farmer preference for maize, rooted in cultural norms, further encouraged maize mono-cropping at the expense of food sufficiency. In conclusion, government incentivising production and marketing of other agronomically suitable crops for the region could reduce food insufficiency.