The WHO states that there are three pillars that determine food security: food availability, food access, and food use and misuse.
Chronic food insecurity: A long-term and persistent condition of food insecurity. Low and irregular incomes are the root cause of urban food insecurity, but inadequate housing and basic infrastructure and limited access to services contribute to levels of malnutrition and food insecurity that are often as high if not higher than in rural areas.
Transitory food insecurity: A short-term and temporary condition of food insecurity.