Fasting Results & Data

Real fasting data from my own fasts and from people around the world, so you can compare experiences and outcomes. I know it’s a ton of graphs 😊

My 10-Day Fast (Aug-Sep 2025)

Ketones and glucose data during the fast

Changes in weight (measured by my Withings floor weight sclae) and body composition (by Dexa scans)

These are my bloodwork results from the final hour of my 10-day water fast. I’ll do another full panel after refeeding (early Oct) and share the results here.

Blood Results

Testosterone (measured at the end of the fast)

Total Testosterone

Jun 2023 - 821 ng/dL (not on the graph)
Dec 2024 - 969
Feb 2025 (end of my previous 9-day fast): 131 ng/dL
May 2025 - 564
Aug 2025, before this 10-day fast: 671 ng/dL
Sep 2025, end of this 10-day fast: 495 ng/dL
Oct 2025, after the 30-day refeed: coming…

Electrolytes (measured at the end of the fast)

My typical daily electrolyte intake during extended fasts - water with pink salt, Ultima electrolytes (2-3 packets) and a bottle of San Pellegrino mineral water

My 7-day (Nov 2024) and 9-Day (Feb 2025) Fasts

Body Weight: 7-Day Fast and Refeeding

Weight Changes: During My 7-Day Fast and Refeeding

Glucose: 7-Day Fast and Then Refeeding

RHR and HRV: 7-Day Fast and Then Refeeding

Body Weight: 9-Day Fast and Refeeding

Ketones: 7-Day Fast and Then Refeeding

GKI: 7-Day Fast and Then Refeeding

Respiratory Rate: 7-Day Fast and Then Refeeding

These are my bloodwork results from the final hour of my 9-day water fast. I tested 52 biomarkers — sometime before my 9-day water fast in February, and then just 30 minutes before breaking the fast. The chart below highlights changes in some key markers (focus on Feb ’25 data; I retested a few in May)

12 biomarkers shifted out of their “optimized” range after the fast — including potassium, vitamin B12, TIBC, ferritin, testosterone, free testosterone, SHBG, white blood cells, total cholesterol, LDL cholesterol, triglycerides, and ApoB