Rapid weight loss usually begins suddenly, and the cause may or may not be known. If you've recently started a new exercise routine, your rapid weight loss may be explained by burning extra calories every day. If you've made no changes to your daily routine, and you experience a rapid or significant weight loss, consult your doctor. Any unexplained weight loss greater than 10 lbs. or more than five percent of your body weight requires evaluation.
Both cancer and cancer treatment may cause rapid, unintentional weight loss. Some cancer-related weight loss is due to a loss of appetite or nausea, while some results from difficulty swallowing or problems with digestion. Lung cancer, pancreatic cancer, leukemia and colon cancer may be especially likely to trigger rapid weight loss in women.
Any condition that interferes with eating, digestion or the absorption of nutrients can lead to rapid weight loss. Peptic ulcers, celiac disease, food allergies, inflammatory bowel diseases and other conditions that result in a loss of appetite, vomiting, diarrhea or malnutrition are possible causes of rapid weight loss in women. While these conditions are typically chronic, in most cases they are manageable with lifestyle changes, dietary modification and medication.
Hyperthyroidism is one of the most common causes of weight loss in women, but any endocrine disorder can lead to rapid weight loss and other symptoms. Diabetes, a disease commonly association with obesity, can cause sudden and dramatic weight loss in some people. In fact, weight loss is sometimes the first sign of the disease.
Some medications list weight loss as a common side effect and other drugs may trigger weight loss by affecting appetite. If your weight loss begins soon after starting a new medication or changing your dose of an existing medication, speak with your doctor. A change in medication may stop your weight loss. Abuse of over-the-counter, prescription and illegal drugs is also associated with sudden and severe weight loss.
AIDS and Other Infections
HIV, AIDS, tuberculosis, parasitic infections and fungal diseases can also cause rapid weight loss in women by exciting the body's immune system, causing it to work harder and burn additional energy. Infections are also likely to negatively affect the appetite.
Fad or Restrictive Diets
While fad diets sometimes cause rapid and dramatic weight loss, the loss is usually temporary and the dieter may end up even heavier once regular eating resumes. These diets often cause side effects and some may even be dangerous.