Weight loss can be intentional, such as with dieting and exercise, or unintentional and be a manifestation of illness. Weight loss can result from a decrease in body fluid, muscle mass, or fat. An decrease in body fluid can come from medications, fluid loss, lack of fluid intake, or illnesses such as diabetes. A decrease in body fat can be intentially caused by exercise and dieting, such as for obesity. Weight loss is normal after pregnancy. The loss of weight and lack of nutrition associated with a chronic illness is referred to as cachexia. Unexplained, unintentional weight loss is often a result of illness and should be evaluated by a healthcare professional.