But because the only loss induced is water, the only gain is dehydration. In addition to causing dehydration, diuretics are also dangerous because they can increase the loss of calcium, potassium, magnesium and zinc from the body. They can also cause a rebound retention of salt and water, making your body more sensitive to diet changes. Ipecac syrup, which is taken to induce vomiting, has been linked to deaths of several patients with eating disorders. Emetine, the active ingredient, can build up in tissue and cause muscle or heart weakness.
Ipecac is toxic, whether taken as a single large dose or as small doses that can build up over time.
Diet pills are often taken to help with weight loss. These reduce appetite, but only temporarily. Typically the appetite returns to normal after a week or two, the lost weight is regained, and the user then has the problem of trying to get off the drug without gaining more weight. Fad diets promise rapid weight loss but actually encourage unhealthy dietary habits. They prey on the dieter's wish for quick results with little effort or make the diet seem exciting because the types of combinations of foods consumed are different from those normally eaten.