Chefs’ decisions can greatly improve the quality of food provided and positively guide diners’ choices. Culinary students’ knowledge of healthy and sustainable nutrition is still scarcely investigated and is limited to the nutritional aspect of the diet, without considering food sustainability or the environmental impact of foods. This study aims to determine the effectiveness of an educational program designed for apprentice chefs. Two questionnaires were administered twice to each student who followed dedicated lectures about nutrition and food sustainability and to other students enrolled as the control group. A total of 264 and 252 apprentice chefs of The School of Italian Culinary Arts—ALMA were enrolled in the control and intervention groups, respectively. At baseline, both groups showed a good level of nutrition knowledge, whereas food sustainability knowledge was lower in all students, regardless of the group. This educational intervention proved to be effective in improving knowledge about nutrition and the environmental impact of food production and consumption. However, a small but significant improvement in nutritional knowledge was also found over time in the control group. Finally, a food sustainability knowledge questionnaire was developed and validated for this study, providing interesting results to be treated as a guide for future developments.