All food and drink
This medical condition is so rare that science has yet to name it, but there are children who are so hypersensitive to food and drink that water is the only thing they can safely consume. One of the most severe and highly publicized cases is that of Kaleb Bussenschutt, a 6-year-old Australian boy who can consume only water, ice and one brand of lemonade. If he eats anything else, he develops ulcers and experiences agonizing stomach pain, so he must receive necessary nutrients through a feeding tube connected directly into his stomach 20 hours a day.
Doctors are baffled by Kaleb's case, but they think he suffers from multiple food allergies and severe malabsorption that makes his body unable to cope with eating food. Food allergies affect about one in 20 children, but the severity of Kaleb's allergy is extremely rare.