Patterns of food insecurity vary among people experiencing homelessness, dependent on interactions between an array of factors like monthly income, regularity of shelter and service access, substance use, and whether they are coping with physical and mental health problems, but broadly speaking homelessness goes hand-in-hand with hunger and malnutrition. Diets tend to be characterized by low consumption of core food groups, like fruits, vegetables, breads, and cereals and high consumption of sugar-sweetened soft drinks and saturated fat. 

Nutrition is a critical element to maintaining both mental and physical health. The effects of poor diet compound problems that people experiencing homelessness already face: higher risk of pnemonia and hypothermia, alongside a weakened immune system which opens them to infectious diseases; vitamin deficiencies and physical symptoms such as dizziness, cracked lips, difficulty walking, and low blood pressure; organ failure; and decreased ability to heal cuts, scratches, and other injuries. Malnutrition has also been shown to negatively affect mood, causing depression, irritability, and fatigue. These symptoms lower peoples' ability to cope with life on the street, and may make it more difficult for them to access housing and services.