What is bulimia nervosa?
Bulimia means eating large amounts of food and then trying to undo the effects by starving themselves, or by vomiting or, less usually, by using laxatives (both known as purging). In extreme cases, someone can be making themselves sick as often as 30 to 40 times a day.
Bulimia is more common than anorexia, but because people keep their weight roughly the same, it’s not so visible.

People are often at great pain to keep the bulimia outwardly hidden. Inwardly, they will be thinking constantly about eating, and having irresistible cravings for particular foods. They dread being fat and believe they should be much thinner than a normal weight.

Contrary to what people believe, taking laxatives doesn’t actually help with weight loss, but removes essential minerals, such as potassium and sodium, which keep the muscles working. Being sick gets rid of less than half the calories consumed, according to one study, and diuretic drugs, which rid the body of fluid, have no effect on the calories absorbed. A flat stomach may be a temporary benefit, but it soon returns to normal when fluid levels rise again.
Media attention has glamorised, and so trivialised, bulimia nervosa. But the effects are not trivial. They include having poor skin, because of being dehydrated, bad teeth caused by stomach acids eroding the tooth enamel, bad breath, a sore throat and mouth ulcers. Periods may also become irregular or stop altogether. Frequent vomiting can cause epileptic fits, muscular weakness and heart problems, while taking a lot of laxatives can also cause permanent damage.