A child’s nutritional status has a significant effect on health and development. While children’s diets in the UK have improved over the past 15 years, some nutritional areas are poor, with significantly low intakes of iron, vitamins A and D and high intakes of foods high in saturated fats and sugars. There are also children who need to adhere to therapeutic and/or restricted diets that increase their susceptibility to nutritional deficiency, and it is these children that this article will address. In particular it covers children with food allergies and intolerance, with a specific focus on cow’s milk protein allergy and lactose intolerance, and those with cystic fibrosis and attention deficit hyperactivity disorder.