Grocery stores and restaurants can control ambient temperatures using air-conditioning. Although questions about how ambient temperature affects consumers’ evaluations of foods are relevant to many food-based businesses, they remain largely unanswered, and there are contradictory hypotheses regarding the influence of ambient temperature on food preferences. Embodiment theory suggests that ambient warm temperature increases food preferences, whereas thermoregulation theory suggests that ambient warm temperature may decrease food preferences to lower the body's temperature by limiting food intake. However, neither of these explanations considers food category. Given that food varies according to whether it is usually eaten warm or cool, the thermoregulation theory leads to the hypothesis that people may try to regulate their body temperature by preferring foods that should be eaten cool and avoiding those that should be eaten warm. To resolve these contradictory hypotheses, this study investigated the effect of warm ambient temperature on preferences for different categories of food. In total, 52 participants in a room with either warm or cool ambient temperature reported preferences for four categories of food images: vegetables, fruits, sweets, and savory foods. The foods were grouped into warm foods (i.e., foods perceived as having a warm temperature: savory foods), cold foods (i.e., foods perceived as having a cool temperature: fruits), and control foods (vegetables and sweets). The results indicated that ambient warm temperatures decreased preferences for savory foods but did not affect preferences for the other foods. The decreased preference for savory foods in warm ambient temperature was based on perceived food temperature but not on tastiness or healthfulness. These findings are the first to establish the effect of food temperature on food preference in warm ambient conditions. Incorporation of food temperature into thermoregulation theory can advance understanding of the sensory influences on consumer behaviors.