Refeeding Syndrome
A dangerous shift in blood salts that can occur when food is reintroduced too quickly after severe calorie restriction — why medical supervision matters on very low-calorie diets.
Plain English
Patient-Friendly Explanation
Refeeding syndrome is a potentially dangerous shift in body salts and fluids that can happen when someone who has been eating very little suddenly starts eating normally again. As the body switches back to using carbohydrates for fuel, it rapidly uses up phosphate, potassium and magnesium, which can strain the heart and nervous system. This is why very low-calorie diets and recovery from severe restriction need medical supervision with food reintroduced gradually.
Medical
Clinical Definition
Refeeding syndrome is a potentially fatal metabolic disturbance that occurs on reintroduction of nutrition (oral, enteral or parenteral) after a period of significant starvation or rapid weight loss. The insulin surge accompanying carbohydrate refeeding drives intracellular shifts of phosphate, potassium and magnesium, while thiamine-dependent glucose metabolism is abruptly activated, producing the hallmark hypophosphataemia together with hypokalaemia and hypomagnesaemia. Clinical consequences include cardiac arrhythmias, heart failure, respiratory failure, seizures, delirium and rhabdomyolysis. Highest-risk patients include those with prolonged fasting or very low intake, rapid or severe weight loss, alcohol use disorder, and patients following very low-calorie diets or recovering from bariatric surgery; prevention relies on identifying risk, giving thiamine before refeeding, slow calorie advancement and close electrolyte monitoring.
Key Insight
Why It Matters
Severe dieting is not simply 'eating less' — restarting normal food intake after very low-calorie eating can be medically hazardous without supervision. Accord Medical's programme monitors patients on very low-calorie diets so this complication is prevented, not treated in hindsight.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: September 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
