Inedia (Latin for fasting) is the ability to live without food, sustaining one's body only on air, sunlight, or "insert mysterious energy force here". There are also some "historical" accounts of this ability, including Roman Catholic saints but not limited to them.
No such claims have ever been shown to hold up against scientific inquiry, when the inquiry is allowed to do its job properly; and that's if we assume that starving someone for the sake of a scientific experiment is even ethical. In the best case scenario, proponents of inedia are lying or cheating by eating food and not telling. This may be intentional deceit or the case of a true believer deceiving themselves. In the worst case scenario, practitioners die from malnutrition or dehydration very quickly.
 See also