Malnutrition can negatively affect clinical outcomes in total hip and knee arthroplasty. Food security plays an important and complex role in nutritional status, and 10.5% of American households are currently food insecure. Rates of food insecurity are higher for women, Hispanic, and Black Americans, those of lower socioeconomic status, and those in rural areas. Undernutrition disproportionately affects the elderly, a cohort with a high burden of osteoarthritis. Strategies for optimization begin with a holistic assessment of the patient's nutritional status. Patients should have a body mass index >18.5 kg/m2, vitamin D level >30 ng/dL, albumin level >3.5 g/dL, transferrin level >200 mg/dL, and total lymphocyte count of >1,500 cells/mm3. We recommend that orthopaedic surgeons screen for malnutrition for all elective total hip/knee arthroplasty patients.