Fasting Safety Screening Tool

Who should not fast without medical supervision

Certain conditions make unsupervised fasting genuinely risky rather than just inadvisable. Type 1 diabetes requires carefully timed insulin administration with meals; extended fasting fundamentally disrupts this balance and can lead to dangerous hypoglycaemia or DKA. Similarly, insulin and sulfonylurea medications actively lower blood glucose — fasting without medication adjustment carries real hypoglycaemia risk.

Pregnancy and breastfeeding impose elevated nutritional demands, and calorie restriction risks insufficient supply for both mother and baby. A history of eating disorders is a particularly important flag: structured fasting regimens can trigger relapse in those with past restrictive eating patterns, even years after recovery.

Conditions requiring a medical check first

Several conditions warrant a GP or dietitian consultation before starting rather than an absolute contraindication. Type 2 diabetes managed with non-insulin medication, chronic kidney disease, recent surgery, and certain cardiac conditions all fall into this category. The concerns are real but manageable with professional guidance rather than requiring complete avoidance.