Learning centre · Safety

Who should not fast — and when to stop

Fasting is not safe for everyone. Know the situations that need a doctor first, and the warning signs that mean "end the fast now".

4 min read · 26 Oct 2026 · தமிழில் படிக்க

Fasting changes how your body uses fuel and how medicines act. For most healthy adults a gentle plan is safe, but some people should not fast without medical supervision.

Please talk to your doctor first if you

• are pregnant, trying to conceive or breastfeeding
• are under 18, or older than 65 with frailty or weight loss
• have ever had an eating disorder (anorexia, bulimia, binge eating)
• are underweight (BMI below 18.5)
• have type 1 diabetes, or take insulin, sulfonylureas (glimepiride, gliclazide, glibenclamide) or SGLT2 inhibitors — these can cause dangerous low sugar or ketoacidosis when you fast
• have heart, kidney or liver disease, low blood pressure, epilepsy, or are recovering from surgery or serious illness
• take medicines that must be taken with food

The health check in this app uses these rules. If fasting is locked for you, that is for your safety — the food diary, body tracking and learning centre are all still yours.

End the fast now if you notice

• dizziness, light-headedness or fainting
• shaking, sweating, sudden hunger or confusion — possible low blood sugar: take juice, glucose or a sweet straight away
• chest pain, tightness or a racing heartbeat
• vomiting, or being unable to keep water down
• a severe headache or unusual weakness

If symptoms are severe or don't settle quickly, seek medical help (in India, call 108).

Fasting is not a treatment

Time-restricted eating can support healthy habits, but it does not cure or reverse diabetes, heart disease or any other condition. Never stop or change prescribed medicines because you are fasting — ask your doctor.

For education only. It does not replace advice from your doctor.