Reasons for unwanted weight loss

Weight may fall when you eat less, absorb fewer nutrients, or use more energy than usual. Dental problems, nausea, difficulty swallowing, medication effects, grief, anxiety and depression can all reduce food intake. Most people with depression notice changes in mood, interest, sleep or appetite as well as possible weight change.

Digestive conditions such as Coeliac Disease and Crohn's Disease can interfere with digestion or absorption. An overactive thyroid can raise energy use and may cause heat intolerance, sweating, tremor or a fast heartbeat. Diabetes can cause thirst and frequent urination; Type 1 Diabetes can develop quickly, while Type 2 Diabetes may be less noticeable at first.

Persistent infection, including Tuberculosis or HIV Infection, may bring fever, night sweats, tiredness or a lingering cough. These possibilities do not mean that weight loss identifies one particular condition; an examination and the pattern of symptoms guide the next steps.

Arrange a primary-care appointment if the loss is not intentional, continues, or has no clear explanation. Before the visit, note when it began, changes in appetite, meals, bowel habits, thirst, urination, sleep, mood, fever and medicines or supplements. Record your weight in similar conditions rather than relying on memory.

A clinician may review your medical history, examine you and decide whether blood tests, urine tests or other investigations are useful. Do not stop prescribed medicine or force large meals without advice. Small, nourishing meals and regular fluids may help while you are waiting, particularly if appetite is low.

Seek urgent medical help for weight loss with severe weakness, confusion, fainting, inability to keep fluids down, severe abdominal pain, difficulty breathing, or signs of marked dehydration. Prompt assessment is also needed for coughing blood, a persistent high fever, or new excessive thirst and urination with vomiting or drowsiness.

Contact a clinician soon if you have ongoing vomiting or diarrhoea, blood in stool, trouble swallowing, repeated night sweats, a persistent cough, or a new lump. Children, older adults, pregnant people and anyone with a long-term condition may need earlier review because reduced intake can affect them more quickly.

You could ask: What might explain the change in my weight and appetite? Which symptoms should I monitor? Do my medicines or supplements need review? What tests are appropriate? How can I maintain nutrition safely while we investigate the cause?