Inside a 72 Hour Fast: The Physiology Behind the Experience

In this episode, MJ is 64 hours into his first 72 hour fast while Ryan, a registered dietitian, walks through what is actually happening under the hood.They dig into what a three day water fast does from a nutrition and physiology standpoint, why MJ feels mentally sharp and energized, and why that does not necessarily mean his brain is operating at full capacity. Ryan breaks down anabolic vs catabolic states, what autophagy really is, why mitochondria matter so much, and how hormetic stress from fasting, movement, ice, and sauna can all trigger similar cellular cleanup.They also get into the messy middle that almost no one talks about:Why some bodies tolerate prolonged fasting better than othersThe real risks of refeeding and electrolyte shifts after a multi day fastWhy eating every 2 to 3 hours is probably not serving your metabolismHow fasting can help some people reshape a mindless relationship with foodWhy fasting can be dangerous territory for those with restrictive patterns, anxiety, or eating disordersThe difference between rhythm and rigid consistency with foodMJ shares what he is learning about his long standing habit of never eating for hunger and always eating until it is gone, and how going 72 hours without food is already shifting his perspective. Ryan, who himself did years of intermittent fasting, talks about why he eventually stopped and what he does instead now to get many of the same benefits without multi day deprivation.If you have ever wondered whether a 72 hour fast is powerful, pointless, or harmful, this conversation gives you both the lived experience and the nuanced science to think it through for yourself.