Peters key takeaways on bone health, calorie restriction and energy balance, dopamine and addiction, gene editing, and testosterone therapy safety with a prostate cancer diagnosis | Quarterly Podcast Summary #3

Our brains are like cactuses that now reside in rainforests. So we evolved in an environment where stimulation was relatively modest and our brains had normal tools for coping with the up and down swings of dopamine, and now we live in the most stimulating environment imaginable. And obviously, we just didn't have enough time to adapt.

When we do something that is difficult that induces pain—and the two examples that she gave were cold immersion and exercise—the body has to offset that pain somehow, and it does so by increasing the endogenous production of dopamine.

How does Anna [Lembke] work with clients? She's a psychiatrist. One of the first steps that she thinks about, and I think this is valuable for any of us that are trying to cope with our own addictions, is she does a four-week dopamine fast, which means a four-week total abstinence from the behavior that one is trying to rid themselves of. She said that 80% of her clients or patients will feel better after the four-week fast.

People have heard me talk a lot about cold plunging. I'm a huge fan of it. Although I still firmly maintain it has no longevity benefit. There's no geroprotective benefit of cold plunging. So to all the biohackers out there, I'm sorry, but I don't think it's going to make you live longer.

No matter what mood I'm in, no matter how foul it is, if I get into a 40-degree bathtub, bury myself to my neck for 10 minutes, I feel insanely good after that.

If you said to me, 'Peter, we have a job for you. You just have to sit in the casino and play blackjack, and we'll pay you a million dollars a month to do this and cover all your losses, and you can keep all the winnings.' I couldn't do it. I couldn't imagine something less appealing.

You take two people with identical genes raised in a completely different environment. And based on that, Anna [Lembke] said that addiction is about 50-60% heritable. That's a huge amount. obviously. But's a big enough amount that it can't be ignored; but it's not so big an amount that the die is cast.

If you struggle with gambling, it's really hard to break a gambling habit if all your friends are gamblers.

I really enjoy alcohol. Like, it's not like I'm repulsed by the taste of alcohol. I quite enjoy it. Like, literally enjoy the taste. I just don't think I could be an alcoholic if I tried. In other words, if you surrounded me with alcoholics, it would never appeal to me to drink in the morning or to drink in a manner that would lead to excessive use.

I really think that having your face dipped in a bowl of cold water... can stimulate the mammalian dive reflex ... Even just covering your face—that can, in theory, I suppose, at least trigger an autonomic response that upregulates the parasympathetic system via the vagus nerve, and that can tone down the sympathetic system.