The effects of different postures on dietary intake when children with severe motor and intellectual disabilities (SMID) eat school meals have yet to be investigated adequately. This study focuses on SMID who are fed through a combination of oral consumption and a nasal nutritional tube, and it compares their dietary intakes when given meals while held in posture by a teacher with those while seated in a cushioned chair. The results show that switching the children’s mealtime postures from one in which they are held to one in which they are sitting in a cushioned chair significantly increases their main and secondary meal intakes, and the children also become able to drink milk that they are unable to drink while being held. When seated in a cushioned chair, the children’s postures remain stable, and it is simple for teachers to assist them with their meals. It may be assumed that with a stable posture, the children’s appetites are not inhibited by stress being exerted on parts of their bodies or changes in posture, and therefore dietary intake increases. Meal intake is involved in children’s quality of life and health maintenance, and therefore it may be assumed that finding a posture suited to each individual child is crucial when assisting them with meals.