A major public health crisis facing America’s society is the increase in child and youth obesity, which has seen a fourfold increase in the last four decades. Major concerns include what children eat for school lunch and what other foods are available in schools. This paper illustrates efforts towards systems change in the luncheon program and food vending machines in the Chicago Public Schools. We discuss the different factors that lead to such changes using the framework of the social ecological model and the soft systems methodology, and we analyze how the resulting innovation was implemented and evaluated. First, we present a theoretical perspective to explain factors that influence children’s eating patterns from a systems approach. Second, we discuss the antecedent factors that lead to systems change. Finally, we examine challenges to systems change, such as resistance to change, different stakeholder priorities, lack of resources, institutional bureaucracy, and unrealistic funder expectations.