The difference between dieting and anorexia is that dieting is a change in eating habits, whereas anorexia is a mental illness. Individuals with anorexia often have a distorted body image and take several steps, including dieting, to bring their body weight down to an unhealthy level. While dieting, particularly crash dieting, is one way in which anorexics reduce their body weight, the two conditions do not have to go hand in hand.
Anorexia nervosa is a serious mental illness in which sufferers use a variety of techniques to lose weight, even beyond the point of being healthy or even meeting normal standards of attractiveness. Individuals with anorexia live in a state of semi or actual starvation, which can cause significant damage to their body systems. In some cases, anorexia nervosa can lead to fatal health conditions, including liver and heart failure.
Some anorexics may choose to lose weight solely through dieting. In such cases, the connection between dieting and anorexia is clear as an individual attempts to lose weight through restricting what she eats. In many cases, the anorexic chooses a low-calorie diet that may restrict calories to as little as 600 to 800 calories per day. In some extreme cases, the anorexic may reduce her calorie consumption even further.
Dieting is not always the means by which an anorexic loses weight. Some anorexics over-exercise, use laxatives, or force themselves to vomit in order to lose weight. In such cases, the connection between dieting and anorexia is not so clear-cut. The anorexic may indeed diet in order to cut calories, but may rely more on other tools and techniques to achieve the severe weight loss desired.
On the other hand, it is quite possible for dieting to be healthy. Individuals who are concerned about their eating habits or who wish to lose weight may decide on a sensible, nutritionally complete diet to help them to achieve their weight-loss goals. Provided that a person's diet allows for safe, slow weight loss and provides the dieter with adequate nutrition, such a diet can be healthy and beneficial. Those who are concerned about determining the difference between dieting and anorexia in someone they care about should pay attention to how that person eats and the amount of weight that he or she loses.
In cases where an individual seems to be trying to lose weight even when she doesn't need to or her weight-loss efforts seem out of proportion to her actual body size, the observer may want to look for other symptoms of an eating disorder. If the individual is losing a significant amount of weight very quickly or showing signs of malnutrition, which can include pale skin, dark circles under the eyes, and hair loss, the friend or observer may want to take action to help that person.