What should you know about causes of sudden loss of appetite?

Viral illnesses such as influenza, COVID-19, gastroenteritis, or hepatitis A can reduce appetite, often alongside fever, nausea, tiredness, diarrhoea, or abdominal discomfort. Gastritis and peptic ulcer can make eating uncomfortable because the stomach lining is irritated. Depression may change appetite with low mood, loss of interest, sleep changes, or reduced energy. New medicines, dental problems, altered taste, stress, and pain can also reduce interest in food. Less commonly, persistent appetite loss occurs with a more serious illness, so the overall pattern matters.

Notice whether the change began suddenly, whether fluids are staying down, and whether there is vomiting, pain, fever, yellowing of the skin, or unintentional weight loss. These details help distinguish a short-lived illness from a problem needing investigation.

Take small, frequent sips of fluid and choose easy-to-tolerate foods in modest portions. Include nourishing options when possible, such as soup, yoghurt, eggs, or a soft meal, and avoid alcohol if you feel unwell. Do not stop prescribed medicine without advice; ask whether a recent treatment could affect appetite. Keep a brief record of food and fluid intake, symptoms, and any weight change so a clinician can judge the pattern.

Seek urgent care for severe or worsening abdominal pain, repeated vomiting, confusion, fainting, black or bloody stools, vomiting blood, difficulty breathing, or signs of dehydration such as very little urine. Arrange a prompt appointment if appetite remains reduced, weight is falling, swallowing is difficult, jaundice appears, or low mood and loss of interest are affecting daily life.

Ask whether your symptoms suggest an infection, stomach condition, medicine effect, mood problem, or another cause. Discuss whether an examination, blood tests, or other checks are needed, and ask how to maintain nutrition and fluids while your appetite returns.