Science8 min read
Autophagy & Fasting: When It Starts, Peaks & How to Maximize It
Learn when autophagy starts during fasting (24-48 hours), how it peaks during a 72-hour water fast, and the science-backed benefits of cellular cleanup.
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Knowledge Base
Science-backed articles on 72-hour water fasting. Learn about autophagy, benefits, safety, and how to get the most out of your extended fast.
Learn when autophagy starts during fasting (24-48 hours), how it peaks during a 72-hour water fast, and the science-backed benefits of cellular cleanup.
Complete guide to the benefits of a 3-day water fast, from weight loss and insulin sensitivity to immune reset and mental clarity.
Step-by-step guide to your first 3-day fast. Preparation, what to expect each day, electrolytes, and how to break your fast safely.
What to eat after a 3-day fast, foods to avoid, and a 48-hour refeeding protocol to maximize benefits and avoid digestive issues.
The truth about muscle preservation during extended fasting. How growth hormone, ketones, and autophagy protect your gains.
How much weight will you lose on a 72-hour fast? We break down water weight vs. fat loss and what the research actually shows.
Understand the risks of extended fasting, who should not fast, and how to minimize dangers during a 72-hour water fast.
A detailed breakdown of what's happening in your body during each phase of a 3-day fast, from fed state to peak autophagy.
Understand the difference between clean and dirty fasting, what breaks a fast, and which approach maximizes autophagy.
Finding your optimal fasting rhythm. Monthly, quarterly, or seasonal? Learn what works best for your goals and lifestyle.
All 10 peer-reviewed studies summarized in plain English
Science Translational Medicine
→ This landmark study from USC tested a fasting-mimicking diet on 100 people. After just 3 monthly cycles, participants saw improvements in markers linked to aging, diabetes, cancer, and heart disease. It's one of the first big human trials showing fasting can actually move the needle on disease risk factors.
Read full paperNature Communications
→ This 2024 study found that fasting cycles can actually make your body biologically younger. Using blood markers that predict biological age, researchers found that people doing monthly fasting-mimicking diets reduced their biological age by about 2.5 years. Your birthday stays the same, but your body acts younger.
Read full paperNew England Journal of Medicine
→ This review from the National Institute on Aging (published in one of medicine's top journals) summarizes decades of fasting research. The big takeaway: fasting triggers a 'metabolic switch' from burning sugar to burning fat, and this switch activates powerful cellular repair processes. It's the scientific foundation for why fasting works.
Read full paperCell Stem Cell
→ This is THE study that put 72-hour fasting on the map. Researchers found that fasting for 2-3 days flips a 'regenerative switch' — it kills off old, damaged immune cells and triggers stem cells to produce brand new ones. It's like rebooting your immune system. This is why 72 hours became the magic number.
Read full paperPLOS ONE
→ The largest fasting safety study ever done — 1,422 people fasting for 4-21 days under medical supervision. The results? Fasting was safe, people felt better emotionally and physically, and side effects were minimal. This is the study to cite when someone says 'isn't fasting dangerous?'
Read full paperObesity
→ This paper explains the 'metabolic switch' in plain terms — what happens when your body shifts from burning sugar to burning fat/ketones. The switch typically happens 12-36 hours into a fast. Once flipped, your body enters a state that promotes fat burning, cellular repair, and brain protection.
Read full paperJournal of the Academy of Nutrition and Dietetics
→ A comprehensive review looking at what intermittent fasting does to human metabolism. The conclusion: fasting improves multiple markers of metabolic health including insulin sensitivity, blood lipids, and inflammation — independent of weight loss. In other words, fasting helps even if the scale doesn't move.
Read full paperNew England Journal of Medicine
→ A classic study from 1970 that mapped exactly what happens metabolically when humans don't eat. It showed that the body is remarkably good at adapting — switching to fat and ketones for fuel while preserving muscle. This paper is why we know the body doesn't just 'eat muscle' during fasting.
Read full paperInternational Journal of Obesity
→ Compared intermittent fasting to regular calorie restriction for weight loss. Both worked for losing weight, but intermittent fasting was better at improving insulin sensitivity and reducing belly fat. This suggests fasting has metabolic benefits beyond just eating less.
Read full paperCancer Discovery
→ Tested fasting in cancer patients receiving chemotherapy. Found it was safe, reduced side effects, and actually boosted the immune system's ability to fight cancer. While more research is needed, this suggests fasting might help cancer treatment work better.
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