<div> <p><span> In this "Ask Me Anything" (AMA) episode, Peter explains some observations he's noticed since switching to a 3-day fasting cycle from the longer fasts, the various things he's measuring, and some helpful tips for getting through a prolonged fast. He also discusses the role of exogenous ketones in fasting and ketogenic diets as well as their impact on autophagy, specifically. Finally, Peter provides some practical advice for those looking to fit exercise for longevity into their busy life. Once again, Bob Kaplan, Peter's head of research, will be asking the questions. If you're not a subscriber and listening on a podcast player, you'll only be able to hear a preview of the AMA.</span></p> </div> <div> <p><br /> If you're a subscriber, you can now listen to this full episode on your <a href="https://peterattiamd.com/members/private-podcast-feed/" rel="noopener noreferrer" target="_blank">private RSS feed</a> or on our website at the <a href="https://peterattiamd.com/ama13/" rel="noopener noreferrer" target="_blank">AMA #13 show notes page</a>. If you are not a subscriber, you'll be able to listen to a sneak peak of this episode.</p> <h2>We discuss:</h2> <div> <ul> <li>Peter's observations since switching from a 7-day to a 3-day fasting regimen [1:25];</li> <li>Ketone measuring devices—blood and breath [7:40];</li> <li>Can zero-calorie sweeteners affect ketone production? [10:40];</li> <li>Will there be a continuous insulin monitor anytime soon? [11:55];</li> <li>Exogenous ketones—Role in fasting and ketogenic diets and their effect on insulin, blood glucose, and autophagy [14:10];</li> <li>5 tips to help you get through a multi-day fast [25:55];</li> <li>Relationship between BHB levels, glucose levels, and autophagy—Are high levels of ketones enough to produce autophagy? [34:10];</li> <li>Why is measuring blood insulin so much harder than blood glucose? [36:55];</li> <li>Advice and resources for people wanting to stay up to date on developments related to health and longevity (and how to quickly sift through all the bad science) [40:10];</li> <li>Advice for those looking to fit exercise for longevity into their busy life [51:10]; and</li> <li>More.</li> </ul> <p>Learn more: <a href="https://peterattiamd.com/">https://peterattiamd.com/</a><br /> <br /> Show notes page for this episode: <a href="https://peterattiamd.com/ama13">https://peterattiamd.com/ama13</a><br /> <br /> Subscribe to receive exclusive subscriber-only content: <a href="https://peterattiamd.com/subscribe/">https://peterattiamd.com/subscribe/</a><br /> <br /> Sign up to receive Peter's email newsletter: <a href="https://peterattiamd.com/newsletter/">https://peterattiamd.com/newsletter/</a><br /> <br /> Connect with Peter on <a href="http://Facebook.com/PeterAttiaMD"><u>Faceboo</u></a><u>k</u> | <a href="http://Twitter.com/PeterAttiaMD"><u>Twitter</u></a> | <a href="http://Instagram.com/PeterAttiaMD"><u>Instagram</u></a>.</p> </div> </div>
Actionable Insights
1. Adopt 3-Day Monthly Fast
Consider switching from a quarterly 7-day fast to a monthly 3-day fast, as Peter Attia found it less intrusive, easier to manage, and allowed for higher exercise tolerance while potentially yielding similar metabolic benefits.
2. Avoid Non-Nutritive Sweeteners
Avoid consuming non-nutritive sweeteners (like those in diet sodas or sugarless gum) during fasting, as they were associated with lower ketone levels and increased misery, potentially impairing ketosis.
3. Adopt Low-Carb Diet
Follow a low-carb diet by avoiding sugar and starch and focusing on vegetables, as this dietary restriction can make it easier to transition into and out of fasting periods.
4. Test Blood After Fasting
Conduct a blood test after a 3-day fast to assess metabolic changes, as a 4-day fast showed similar signature findings (e.g., very low insulin, glucose, IGF-1, free T3, testosterone; very high uric acid, reverse T3) to longer fasts.
5. Maintain Fasted Exercise Intensity
During 3-day fasts, exercise tolerance seems higher, allowing for intense workouts (e.g., two hours of sled work, deadlifts, compound movements) without significantly reducing volume, unlike longer fasts.
6. Use Ketone Tests as Guide
Use ketone testing primarily as a guidepost, finding it more helpful for achieving nutritional ketosis than for strict monitoring during fasting, where its relevance for actionable changes is less clear.
7. Choose Accurate Ketone Meter
When measuring blood ketones, consider using the Precision Xtra device as it appears to be more accurate at lower ketone levels compared to Keto Mojo.
8. Consider Breath Ketone Testing
If cost or aversion to finger pricking is a concern, breath ketone testing offers a cheaper and more accessible alternative to blood ketone testing, though historical correlation with blood BHB has been poor.
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