Qualy #43 - What are Peter's thoughts on fasting and ketosis for females?

**Peter Attia** (0:05)
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**SPEAKER_1** (1:05)
What are your thoughts on fasting and ketosis for females?

**Peter Attia** (1:08)
Well, again, a real tough question, because I find all questions of nutrition to be so individual that it's hard to answer them sort of in a one-size-fits-all, sort of one-stop-shop approach. That said, I think there are a couple things women need to be thoughtful about. If any woman is having an issue with fertility, I couldn't make a case, I can't make a very compelling case for nutritional ketosis if a woman is trying to get pregnant. And I'm sure this is just going to piss off a lot of the keto herd, but, because of course if you're in the keto cult, you believe that ketosis is the optimal state for everything, including global warming. But the reality is if you look at the FGF levels, and also if you just think about it from an ancestral standpoint, the higher the level of ketone during our evolution, the more likely we were separated from food.
And the more likely you're separated from food, the less genetic pressure you should have to be reproducing at that point in time.
And this concept is so well preserved in biology. I mean, we had a great discussion with David Sinclair recently to talk about this, and it's even true in the case of the sirtuins, which would be one of the more important regulators of our aging and including our reproductive stress. So I think when you look at the FGF21 data and the ketosis data, there's a very, and I don't want to bastardize this, because I wish I'd known that I was going to be asked this question, I would have looked up the paper. It's from a researcher in Texas. I think he's at, he might be at UT Southwestern, but if you search, and his first name is David. I'm blanking on his last name. Begins with an M, though. But if you-

**SPEAKER_1** (2:48)
Mangelsdorf?

**Peter Attia** (2:49)
Yes, yes, yep, that's him. I saw him present at a meeting once, and it was remarkable data that looked at the differences in a male and female brain in the presence of changing FGF21 levels. And it was so cool to see this difference. The pituitary gland is one of the very few pieces of tissue in the body that has what's called portal circulation, the liver being the other one. So the pituitary has a direct connection via the pituitary stalk to the hypothalamus. The long and short of it is, in a cholera-restricted state, when ketones are elevated, it suppresses FSH and LH in women but not in men. This is super interesting to me, and it has a profound evolutionary, I mean, again, maybe I'm just making up a story to fit this, but if we're gonna subscribe to any of Occam's razor, this would be a great application.
In a period of famine, you would want women to stop reproducing. You would want to shut off FSH and LH. You would want men to have no impairment on their testosterone level. That's all the more time that they should be out there and able to get food. So again, I've always been kind of a little bit careful of suggesting that a woman who's trying to get pregnant be in ketosis. Now look, I know what's gonna happen. Everyone's gonna say, well, I got pregnant when I was in ketosis. Yeah, obviously it's possible. I mean, I'm not suggesting it's not, but if we're talking about optimization, the second thing of course is, should a woman be in ketosis during pregnancy? And the answer is, I simply don't know the answer. Clearly, we evolved with mothers being in ketosis and having children. I mean, it'd be impossible for our species to be here if mothers were not in ketosis during pregnancy. I mean, we didn't have buffets.