Poor nutrition predisposes to infection, and various food compounds, such as micronutrients, are key elements of immune competence. A large number of scientific publications have suggested a role of phytochemicals, food bioactives and nutrition in combating the current coronavirus pandemic. Various dietary components and specific food supplements have been proposed to be helpful in the prevention or therapy of COVID-19. While findings in preclinical models suggest that food bioactives and micronutrients may potentially augment viral defense, evidence supporting antiviral and immunomodulatory efficacy of these compounds in the prevention or management of COVID-19 is non-existent. Large-scale epidemiological and well-designed clinical studies investigating dosage and combinations of food compounds in different age groups and populations are needed before any recommendations can be made. Both malnutrition and overnutrition can adversely affect the immune system. Malnutrition at population level appears to be associated with elevated rates of fatal outcomes of COVID-19. Obesity and non-communicable diseases have been found to be a prognostic risk factor associated with worse COVID-19 outcomes. A focus on obesity and nutrition-related chronic diseases should be a key element of public health. This approach would be more effective than the far less promising search for food bioactives with potential immune-supportive efficacy.