When should you see a doctor about unintentional weight loss?

Unintentional loss can happen when the body absorbs less nutrition, uses energy differently, or appetite falls. Coeliac disease and Crohn's disease may cause digestive symptoms. Hyperthyroidism can bring heat intolerance, palpitations or restlessness. Type 1 diabetes may cause thirst and frequent urination; type 2 diabetes can also affect weight and energy. Depression, HIV infection and tuberculosis are other possibilities a clinician may consider.

Record when the change began, appetite, meals, bowel symptoms, thirst, urination, fever, cough, mood and medicines. Note whether clothes fit differently and whether daily activities feel harder. Keep eating and drinking regularly if you can, and seek advice before using supplements if swallowing or digestion is difficult.

Seek urgent help for weight loss with severe weakness, confusion, fainting, persistent vomiting, inability to keep fluids down, or deep rapid breathing. Arrange prompt medical care for coughing blood, prolonged fever, night sweats, marked thirst with frequent urination, or worsening abdominal pain.

Ask what examination and tests may help explain the change, whether nutrition support is needed, and which symptoms should trigger urgent review. Mention digestive changes, mood, sexual-health concerns, travel, family history and any recent medicine change.