Medical causes of rapid weight loss

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Although most people are probably more upset when their clothes begin fitting tight rather than baggy, there are others who are rightfully concerned about why their clothing suddenly feels looser. For some mysterious reason, they're rapidly losing weight. Involuntary weight loss can be due to various medical conditions. Reasons may range from physical illnesses to eating disorders such as anorexia. While losing weight deliberately in a healthy manner is a positive action, taking off pounds too quickly and unintentionally can be unhealthy.


Weight loss linked with diabetes can be intentional or unintentional. People with type 1 diabetes don't produce enough insulin, while type 2 diabetics aren't able to properly manage insulin. Often, when type 2 diabetics are placed on diabetic diets, they lose weight. However, weight loss for type 1 diabetics is usually unintentional. Because of their high sugar levels, type 1 diabetics can dehydrate and therefore drink more water, causing them to urinate frequently and lose weight quickly. Also, because of a lack of insulin, the cells starve. Therefore, for the body to produce energy, it has to burn off fat cells, causing rapid weight loss.

Cancers Causing Rapid Weight Loss

Several types of cancers can cause rapid weight loss. According to the online medical library Merk Manuals, some cancer patients experience weight loss even though they may have a good appetite. Others lose weight because of decreased appetite and nausea or as a result of swallowing difficulties. Some common cancers causing rapid weight loss include lung cancer, colon cancer, pancreatic cancer and leukaemia. Cancer patients undergoing chemotherapy and radiation treatments may also experience appetite loss, resulting in rapid weight loss.

Human Immunodeficiency Virus

The human immunodeficiency virus (HIV), which causes AIDS, is another severe medical problem that usually leads to poor appetite and weight loss. The bodywork harder to fight infections when the HIV attacks the body's immune system. As a result, people with HIV have additional energy and nutrient requirements, with the infection increasing the body's need for food. If HIV patients don't eat more to meet the body's extra demand for nutrients and energy, rapid weight loss can occur.

Other Diseases Causing Rapid Weight Loss

Conditions such as coeliac disease, irritable bowel syndrome and colitis (Crohn's disease) are diseases that can cause gastrointestinal complications, digestive problems and continual diarrhoea. Typically, these are signs of the body not being able to normally absorb food nutrients across the gastrointestinal tract. As a result, rapid weight loss can occur. Tuberculosis is another disease commonly known for weight loss as this lung disease can cause appetite loss.

Hyperthyroidism and Stress

Hyperthyroidism, which is a hormone imbalance, involves a condition of the thyroid gland overproducing particular hormones, leading to rapid weight loss. When the body is soaked in too much thyroid hormone, body metabolism increases, in addition to increased physical activity. While some people gain weight while stressed, others lose weight because they eat less. Although it's rare, in some cases, stress can cause the thyroid gland to be hyperactive. This stimulates appetite, causing the body to burn calories at a faster rate than normal.


Anorexia is a serious eating disorder where people starve themselves, resulting in rapid weight loss. According to the Cleveland Clinic, someone is considered anorexic when body weight is at least 15 per cent less than what's considered a normal weight. Besides leading to severe health problems, anorexia can also be fatal. One of the main symptoms someone is anorexic is the body weight isn't consistent with age, height and build. Other symptoms include brittle skin, shortness of breath, refusing to eat in public, weakness and being obsessed with calorie intake.


Some medications such as antidepressants can cause rapid weight loss. Amphetamines, thyroid medicines and chemotherapeutic agents are other medications that can lead to unintentional and quick weight loss. Since the early 1950s, doctors have been prescribing prescription drugs for weight loss. These medications increase serotonin levels in the brain, giving the brain the message the stomach is full. This decreases a person's appetite so he eats less and the metabolic rate increases, resulting in weight loss. However, these medications should be taken with caution and carefully monitored by a doctor.

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