Unintentional weight gain occurs when you put on weight without increasing your consumption of food or liquid. It is often caused by:

  • fluid retention
  • abnormal growths
  • constipation
  • pregnancy
  • quitting smoking

Unintentional weight gain can be periodic, continuous, or rapid.

Continuous unintentional weight gain is often the result of pregnancy. Periodic unintentional weight gain includes regular fluctuations in weight like those experienced during a woman’s menstrual cycle.

Most people who quit smoking gain 4 to 10 pounds in the first 6 months after quitting. Some gain as much as 25 to 30 pounds. This weight gain is not simply due to eating more.

Although many cases of unintentional weight gain are harmless, the symptoms experienced in conjunction with rapid weight gain may signal a medical emergency. Rapid unintentional weight gain may also be caused by medication side effects.

Depending on the cause, symptoms of unintentional weight gain can differ from person to person. Symptoms often associated with this type of weight gain include:

  • abdominal discomfort
  • abdominal pain
  • bloating
  • flatulence (gas)
  • constipation
  • visible swelling in the abdomen or other areas of the body
  • swollen extremities (arms, legs, feet, hands)

If you experience any of the following serious symptoms, seek medical care immediately:

  • fever
  • skin sensitivity
  • shortness of breath
  • difficulty breathing
  • swollen feet
  • heart palpitations
  • sweating
  • changes in vision
  • rapid weight gain


Your doctor will ask several questions regarding your symptoms, lifestyle, and medical history to pinpoint what might be causing your weight gain. Your doctor also may take a blood sample to test for the presence of infection. He or she will also likely check your blood for hormone levels.

An imaging test such as an ultrasound, X-ray, MRI (magnetic resonance imaging), or CT scan (computed tomography scan) may be necessary. These tests help to determine whether a fracture, abnormal growth, rupture, or inflammation is to blame.



Treatment depends on the cause of the unintentional weight gain.

If a hormonal imbalance is to blame, your doctor may prescribe medication to balance your hormone levels. The type used depends on which hormones are affected. These medications are often used long-term.

For those who gain weight after quitting smoking, adjustments in diet and eating habits can help.

If medication is causing the problem, your doctor will possibly recommend alternative treatments.

In some cases, other surgeries may be necessary. Cysts, tumors, ruptures, and fractures may all require surgery for repair or removal. The type of surgery needed depends on the nature of the condition.

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