Unexplained weight loss is a noticeable drop in your body weight without trying. And it’s not just a little weight — it’s a loss of 10 pounds or 5% of your body weight in six to 12 months. It can be a symptom of a serious illness, like cancer or diabetes. Treatment involves identifying and treating the condition that’s causing it.
Unexplained weight loss is a noticeable drop in body weight when you’re not trying to lose weight. You’re not on a calorie-limited diet. In fact, you haven’t made changes to what or how much you’re eating. And you haven’t become more active recently.
Unexplained weight loss is concerning if you lose more than 5% of your body weight or 10 pounds over six to 12 months, especially if you’re over age 65. Most people gain and lose a little weight from day to day, but these changes tend to stay within a five-pound range. However, if you’ve lost more than that without trying, there might be something else going on.
Unexplained weight loss is a red flag because it’s a common symptom of many serious illnesses. These diseases often get worse (progress) in stages. Some diseases — like diabetes or Addison’s disease — can progress quickly. Others — like cancer — may progress more slowly. Seek medical care as soon as you notice that you’ve lost 10 pounds or more than 5% of your body weight without trying to. This will give you the best chance of recovery.
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Several health conditions can lead to unexplained weight loss. Some conditions reduce your appetite, while others prevent your body from absorbing calories, or increase the rate at which you burn calories.
Possible causes of unexpected weight loss include:
A healthcare provider may order specific medical tests based on your symptoms, family history and other factors. For example, if you have symptoms of a peptic ulcer, your provider may recommend an upper endoscopy.
Other tests may include:
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Your treatment for unexplained weight loss depends on what’s causing it. For example, if you have a toothache, you may need to see a dentist. If the cause is a peptic ulcer, your provider may treat it with antibiotics. People with celiac disease must avoid all gluten.
If you’re losing weight and don’t know why, don’t try to treat it at home. See a provider to find out the cause so you can receive the treatment you need.
Many of the conditions that lead to unexplained weight loss can’t be prevented. But there are some steps you can take to help prevent some of them, including:
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Always see a healthcare provider if you lose weight without trying. Unexplained weight loss is often a sign of a health condition that requires treatment.
A note from Cleveland Clinic
Losing weight unexpectedly may seem like a good thing, so you might be tempted to ignore it. But don’t let this symptom go. You might need important medical care — and in most cases, the cause is manageable with treatment.
Contact your healthcare provider and discuss your symptoms and health history. You may need one or more medical tests to get a diagnosis. After your provider finds the cause, they’ll work with you to determine the best treatment. Treating the underlying condition causing the weight loss can help you regain weight and start feeling better.
Last reviewed on 08/05/2024.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy