The purpose of this inquiry was to develop substantive theory that describes the social process that influences the eating behavior of hospitalized older adults. Undernutrition or the inadequate intake of dietary nutrients necessary to maintain health, contributes to negative health outcomes such as increased morbidity and mortality in hospitalized older adults. Inadequate dietary intake is a risk factor for undernutrition. Despite the availability of vast resources within the hospital environment, hospitalized older adults have inadequate dietary intake. Undernutrition has been studied from a dietary intake perspective; however, why dietary intake remains inadequate is unknown. Inquiry of eating behavior and the social process that influences eating behavior will provide insight into why dietary intake remains inadequate. The Quality Health Outcomes Model was the conceptual framework that guided this inquiry. A qualitative, grounded theory methodology was used to investigate this phenomenon. Participants included acutely ill, hospitalized older adults and their healthcare providers. Field work included observation, interview, and document review to better understand the actions, interactions and perceptions of participants as to the process that influenced hospitalized older adult eating behavior. Datum was compared, coded, and analyzed using the constant comparative method. The Theory of Compromised Eating Behavior was developed and describes the process of compromise older adults experience related to eating behavior while hospitalized. The Theory has four stages: self-indication, joint-action, negotiation, and action. Hospitalized older adults choose to compromise their health should they eat inadequately or alternatively compromise their acculturated foodways should they eat adequately. Additionally, healthcare providers compromise their beliefs when older adult patients do not eat adequately. Older adults are at risk for negative health outcomes due to inadequate dietary intake while hospitalized. The meaning of hospital food and mealtimes differs from traditional food and mealtimes for the older adult, resulting in compromise. Intervention which enhances the meaning of food and mealtimes for the older adult during hospitalization may improve dietary intake and nutritional outcomes.