Viral infection and loss of appetite

Your body may temporarily make food less appealing while it responds to infection. A blocked nose can dull smell, fever can increase tiredness, and nausea, vomiting or diarrhoea can make eating uncomfortable. Loss of appetite is a common presentation of illnesses such as influenza, gastroenteritis and COVID-19, but it can also occur with non-infectious problems including gastritis, depression or a peptic ulcer.

Small changes matter: feeling thirsty, passing less urine, having a dry mouth or becoming light-headed can suggest dehydration. Appetite may return gradually rather than all at once. Persistent or worsening appetite loss needs assessment because other conditions, including hepatitis A or pancreatic cancer, can also affect eating.

Prioritise fluids in frequent small sips. Water, oral rehydration solution, clear soup or another tolerated drink can be easier than a large glass. Try small portions of soft, familiar foods when able, such as yoghurt, toast, rice, soup or fruit; do not force a full meal.

Rest, ventilate shared spaces and follow infection-control advice relevant to your symptoms. Avoid alcohol, and check with a pharmacist before taking medicines if you are vomiting, dehydrated, pregnant or managing a long-term condition. Keep a simple record of drinking, urination and symptoms so a clinician can see whether you are improving.

Seek urgent help for trouble breathing, confusion, fainting, severe weakness, severe abdominal pain, blood in vomit or stool, or an inability to keep fluids down. Arrange prompt medical advice if you are passing very little urine, becoming increasingly drowsy, losing weight without trying, or the appetite problem is not easing as the infection improves.

Children, older adults, pregnant people and anyone with diabetes, kidney disease or another condition affecting hydration may need advice sooner. A clinician can examine you, review medicines and decide whether tests are needed.

Could my symptoms fit a viral illness, or do they suggest another cause? How can I replace fluids safely, and which warning signs should prompt urgent care? Do any of my medicines or existing conditions change what I should eat or drink?