Medical Disclaimer

The site publishes two things: my own fasting schedule as I actually followed it, and my own biomarker readings — weight, blood pressure, VO2 max, DEXA body composition, blood panels, breath ketones. The articles summarise what I read while trying to understand those numbers.

That is a sample size of one, uncontrolled, unblinded, and unsupervised. It cannot tell you what fasting would do to your body. Where an article cites published research, that research describes populations and averages — not you.

Fasting is unsafe for a lot of people. This list is not exhaustive:

• Anyone who is pregnant, trying to conceive, or breastfeeding
• Children and adolescents under 18
• Anyone with a history of an eating disorder, or a difficult relationship with food
• People with type 1 diabetes, or type 2 diabetes managed with insulin, sulfonylureas or SGLT2 inhibitors
• Anyone underweight, frail, or recovering from illness, surgery or injury
• People with kidney or liver disease, heart failure, or a history of arrhythmia
• Anyone taking medication that must be dosed with food, or that affects blood pressure, blood sugar, electrolytes or blood thinning
• Anyone over 65 without clinical supervision

If any of these describe you, do not use this site as a guide. Extended fasting can cause dangerous drops in blood sugar and blood pressure, electrolyte disturbance, and — on refeeding after a long fast — refeeding syndrome, which can be fatal.

• Fainting, near-fainting, or repeated dizziness
• Chest pain, palpitations, or an irregular heartbeat
• Confusion, slurred speech, or unusual difficulty concentrating
• Severe or worsening headache that does not settle with fluids and electrolytes
• Persistent vomiting, or inability to keep water down
• Muscle cramps or weakness that keep getting worse
• Very dark urine, or passing almost no urine

In an emergency call your local emergency number. Do not wait to “finish the fast”.

The fasting weight loss calculator produces rough estimates from standard published equations. It is a teaching tool for understanding why the scale moves during a fast, capped deliberately at 72 hours. It is not a plan, a target, or a prediction for your body.

Reading this site, emailing me, or commenting on a video does not create a doctor–patient or professional relationship. I cannot answer questions about your health or medication, and I won’t try. By using the site you accept that any decision you make about eating or fasting is your own, taken at your own risk — see the terms of use.