Summary
Siim Land joins Kris Gethin to discuss how intermittent fasting and autophagy can be combined with serious bodybuilding without sacrificing muscle mass. They cover the science of metabolic autophagy from Siim's 500-page book, practical fasting windows for lifters, and how to bridge the gap between optimizing longevity and building an impressive physique.
Key Points
- A 16-20 hour daily fasting window activates autophagy while still allowing enough feeding time to hit protein targets for muscle growth.
- Protein intake should be concentrated in the eating window at 1.6-2.2g per kg of bodyweight to preserve lean mass during fasting.
- Autophagy clears damaged cellular components, but chronic caloric restriction or excessive fasting can impair muscle protein synthesis.
- Resistance training in a fasted state can amplify AMPK activation and autophagy, but performance may suffer without pre-workout fuel.
- Cycling between periods of higher calories (building phases) and fasting-focused phases may optimize both longevity and hypertrophy over time.
- Coffee and green tea during the fast can enhance autophagy through polyphenol activation of AMPK without breaking the fast.
Key Moments
Balancing mTOR and AMPK for muscle and longevity
Siim Land explains how to bridge bodybuilding and longevity by cycling between mTOR stimulation for muscle growth and AMPK activation through fasting on a daily basis.
"the key is in the balance finding this balance on a daily basis where you stimulate both the aspect of building muscle with muscle"
Autophagy is not an on-off switch — BCAAs during fasting
Land debunks the misconception that one gram of BCAAs completely shuts down autophagy, explaining that basal autophagy occurs constantly and small inputs only temporarily shift the mTOR-AMPK balance.
"one of the misconceptions about autophagy is that that it's almost like this on an off switch"
Using fasting strategically during travel for circadian reset
Land describes fasting during flights as a convenient biohack that avoids airport food and helps rapidly reset circadian rhythms when arriving in a new time zone.
"usually I usually I usually have them when I'm like traveling so it's very convenient like I'm not going to want to eat like airport foods or subway or something so I'd much rather fast"
Growth hormone during fasting protects muscle from catabolism
Land explains that fasting elevates growth hormone which acts as an anti-catabolic hormone protecting against muscle breakdown, and that autophagy itself can protect against sarcopenia through hormesis.
"growth hormone is in economic you build muscle it's more of like an anti-catabolic hormone that protects against muscle protein breakdown and it promotes fat loss"
