Loss of appetite and weakness: what to know

Eating less can reduce the energy and fluids available for normal activity. Dehydration, fever, vomiting or diarrhoea can add dizziness and muscle fatigue. Viral illnesses such as influenza or COVID-19 may reduce appetite while causing tiredness. Low mood, stomach problems, medication effects and other health conditions can produce a similar pattern.

Weakness may mean general lack of energy, or it may be trouble moving one limb or one side. Note which you feel, how quickly it started, and whether you have fever, pain, breathlessness, palpitations, vomiting or changes in urine.

Rest, take regular sips of fluid, and choose small meals containing a mix of carbohydrates and protein when tolerated. Sit down before standing, rise slowly, and ask someone to help if you feel unsteady. Keep a note of intake and symptoms so a clinician can assess the trend.

Avoid strenuous activity while dizzy or markedly weak. Do not start supplements or change medicines as a substitute for assessment; a clinician may need to review hydration, nutrition, infection and other causes.

Arrange a review if weakness persists, appetite does not return, you are losing weight without trying, or daily tasks become difficult. Seek emergency help for sudden one-sided weakness, facial drooping, speech trouble, chest pain, severe breathlessness, fainting, confusion, inability to keep fluids down, or very little urine.

Ask whether your weakness sounds general or neurological, whether dehydration or infection is likely, how to rebuild intake safely, and which symptoms should lead you to emergency care.