Those of you who are not bone-thin would probably welcome a bit of unexpected weight loss—especially if it meant you doing nothing to change your usual habits. But the truth is that unexplained weight loss can be a warning sign of a serious illness, or of an imbalance in your system.

If you or someone you know has experienced weight loss recently and can’t find an explanation for it, take a look at some of these common symptoms and see if anything resonates with you. Of course, this list is not comprehensive - it’s always strongly recommended that you visit your doctor to find out more.

Unexplained weight loss could be tied to your mental health. But this is often hard to recognize, because there are no other physical symptoms, like chronic pain or a change in skin coloration. Mental health issues that can lead to excessive weight loss include the following, and can be treated with therapy and/or drugs:

• Grief

• Anxiety

• Depression

• Anorexia nervosa

Chronic conditions affecting your digestive system can lead to weight loss that cannot otherwise be explained. The following are some symptoms that, when connected with unexplained weight loss, can be a sign of a digestive issue.

• Diarrhea, constipation or other bowel problems

• Belching, flatulence, indigestion or heartburn

• Nausea and/or vomiting

• Abdominal pain or swelling

These can be signs of:

• Stomach ulcer

• Inflammatory bowel disease

• Chronic liver disease

• Malabsorption

• Diabetes, Type 1 or Type 2

• Hyperhtyroidism

• Cancer of the stomach, gallbladder, pancreas or liver

• Gastrointestinal disease

• Endocrine disorders

The elderly can also suffer from excessive weight loss for a variety of reasons:

• Ill-fitting dentures

• Alzheimer’s

• Dementia

• Stroke

• Neglect

• Difficulty preparing meals

• Inability to purchase food, whether because of money problems or physical problems

Weight loss can also occur in people of any age because of medications they have been prescribed. If you’ve recently started medication, or if your doctor has started you on medication, and you’ve experiences weight loss, contact your doctor and let them know.

Tapeworms, which can be contracted from undercooked fish, pork or beef, can cause unexplained weight loss. Symptoms of tapeworms range from none at all to constant hunger but with no weight gain, abdominal pain, digestive problems or worms in stool.

While this information is not meant to scare you, it is important to know that if you’ve been losing weight rapidly without dieting, there might be a serious reason for it. In short, no weight loss is unexplained. See your doctor if things get really weird.