Peter Attia MD#02 – Rhonda Patrick, Ph.D.: paradox of IGF-1, ketogenic diets and genetics, benefits of sauna, NAD+
At a glance
WHAT IT’S REALLY ABOUT
Rhonda Patrick and Peter Attia revisit IGF-1, ketosis, sauna, fasting
- Both speakers have moved away from the idea that chronically low IGF-1 and constant caloric restriction are the best route to healthspan, favoring cycling between low and high IGF-1 through fasting, refeeding and exercise.
- They discuss why ketogenic diets backfire in some people, with Attia describing patients whose LDL particle number and inflammation rose until saturated fat was swapped for monounsaturated fat, and Patrick suggesting PPAR and FTO SNPs as possible explanations.
- Patrick describes Valter Longo's work on prolonged fasting and the fasting-mimicking diet, including organ shrinkage and regrowth, stem cell activation, and reduced chemotherapy toxicity, and Attia adds a mouse surgery study where brief fasting improved survival.
- Sauna use, cold exposure and exercise are covered, including Finnish observational data on cardiovascular mortality, the role of IL-6 and dynorphin, and the possibility that cold after strength training blunts hypertrophy.
- The conversation closes on NAD+ precursors and open research questions, including how often and how long to fast and what rapamycin dose and frequency are best, with both speakers calling for better biomarkers.
IDEAS WORTH REMEMBERING
5 ideasChronically low IGF-1 may not be ideal for healthspan.
Patrick cites Longo's work and a lemur caloric-restriction study showing brain gray matter atrophy, while Attia points to epidemiology where mortality is lowest at moderate-to-high IGF levels, so both now favor cycling rather than constant suppression.
Refeeding matters as much as fasting.
Patrick explains that low IGF-1 activates stem cells during a prolonged fast, but IGF-1 is then needed during refeeding for proliferation and repopulation of tissues such as the immune system.
Some people respond badly to standard ketogenic diets.
Attia describes roughly 10 to 20 percent of patients whose LDL particle number and inflammatory markers rise on a high-saturated-fat ketogenic diet and normalize when saturated fat is replaced with monounsaturated fat; Patrick says SNPs in PPAR alpha, PPAR gamma and FTO affect responses to saturated versus unsaturated fat and that fewer than 20 percent of people carry them.
Protein, not just carbs, often prevents ketosis.
Attia says that among the 50 or 60 patients he has followed closely on ketogenic diets, protein was almost always the bigger problem, and that some non-producers of ketones improved with fasting plus hard exercise that depletes glycogen.
Exercise is central to brain health and to using IGF-1 well.
Attia says a literature review he co-authored found exercise to be the most compelling intervention for brain health, and Patrick notes exercise directs IGF-1 to muscle and brain and that 24 HIIT sessions raised VO2 max by 12 percent in one study.
WORDS WORTH SAVING
5 quotesBecause if you're really thinking about science, you have to understand, of course, that virtually all facts have a half-life, and our knowledge is constantly evolving.
— Peter Attia
So five years ago, I would have said, "IGF is the devil. Growth hormone is the devil. You want them to be as low as possible." I'm not convinced of that today
— Peter Attia
Everything we've talked about, if you really stop to think about it, comes down to how could you target this tissue and leave that tissue alone, or how could you target this cell and leave that cell alone?
— Peter Attia
It's not hard to kill a cancer cell with a chemical. That's trivial. It's hard to kill a cancer cell and not a normal cell.
— Peter Attia
It's enjoyable until you're like, "Holy shit, it's hot. I want to get out."
— Rhonda Patrick
High quality AI-generated summary created from speaker-labeled transcript.
