What is the ruling on girls intentionally vomiting after eating for fear of gaining weight?

Eating beyond satiety is forbidden extravagance, as Allah says: (And eat and drink, but be not excessive). Eating beyond satiety has no benefit; rather, it is harmful and resembles throwing food into the trash. Whatever exceeds a person's need, others have a right to it, and it may lead to illness. Wasting food after consuming it, if it becomes a habit, is forbidden due to its extravagance. There are other ways to lose weight that do not waste Allah's blessings.