A crash diet is a diet which is extreme in its nutritional deprivations, typically severely restricting calorie intake. It is meant to achieve rapid weight loss and may differ from outright starvation only slightly. They are not meant to last for long periods of time, at most a few weeks. Importantly, the term specifically implies a lack of concern for proper nutrition. Now contrary to the belief of many who start this diet, this form of dieting is neither healthy nor successful in achieving weight loss. While some weight might be lost, this weight is usually gained back very quickly in the weeks that follow this diet. But on the other side, the weight will stay off if one exercises and maintains a proper diet afterwards, and watches their fat calorie intake after stopping the diet.