Losing weight without trying: am I sick?

Weight can fall when appetite changes, swallowing is difficult, food is poorly absorbed, or the body uses more energy during illness. Mood problems, dental trouble, thyroid disease, infection and medicine effects are also possible. Unexplained weight loss is a presentation of several conditions, including bowel cancer, lung cancer, lymphoma, leukaemia, pancreatic cancer and cancer of unknown primary; it does not show which condition is present.

Book an appointment if the change continues, is noticeable to you or comes with reduced appetite, fatigue or other symptoms. Record when it began, your usual meals, bowel changes, medicines, swallowing problems and any fever or pain. A clinician may examine you and choose blood tests, scans or other investigations according to your history.

Seek prompt medical help for inability to swallow fluids, repeated vomiting, black or bloody stools, severe abdominal pain, marked weakness, fainting, confusion or breathing difficulty. Arrange timely review for ongoing weight loss with a new lump, persistent cough, jaundice, night sweats or a sustained change in bowel habits. These features need assessment, not self-diagnosis.

What causes fit my symptoms and medicines? Could swallowing, digestion or mood be contributing? Which examination or tests are appropriate? How can I maintain nutrition safely? What change should prompt an earlier appointment?