The Peter Attia Drive - #157 - AMA #22： Losing fat and gaining fat： the lessons of fat flux

00:00:00.000 Hey everyone, welcome to a sneak peek, ask me anything or AMA episode of the drive podcast.

00:00:16.500 I'm your host, Peter Atiyah. At the end of this short episode, I'll explain how you can

00:00:20.460 access the AMA episodes in full, along with a ton of other membership benefits we've created,

00:00:25.440 or you can learn more now by going to peteratiyahmd.com forward slash subscribe.

00:00:31.140 So without further delay, here's today's sneak peek of the ask me anything episode.

00:00:39.060 Hey everyone, welcome to ask me anything number 22, AMA number 22. I'm once again joined by Bob

00:00:46.760 Kaplan. In today's episode, we discuss fat flux, which is really technical speak for how fat enters

00:00:53.920 and exits a fat cell, which is exactly what determines how big a fat cell is. And how big 0.98

00:00:59.880 a fat cell is, is what determines how much fat a person is carrying. So anytime you hear somebody

00:01:04.400 say, I want to lose weight, what they're really saying is I want to lose fat mass. And what that

00:01:10.480 really means is I want my fat cells to be smaller. So if you want to understand how that works,

00:01:15.460 this is an episode that's probably for you. Again, we go into it in a staggering amount of detail.

00:01:21.340 This is accompanied by some slides. So if you're watching this on video, you'll see those. If not,

00:01:28.020 you'll see them in the show notes. I recommend checking that out. Also, this video will be

00:01:32.180 available in its entirety to the subscribers in the show notes section. If you're not a subscriber,

00:01:37.680 but you still want to see part of the video, it's going to be on YouTube on our YouTube channel.

00:01:40.740 So without further delay, I hope you enjoy AMA number 22.

00:01:49.840 Are you ready for another AMA?

00:01:52.380 I am. I see the agenda and I'm going to share my concern upfront, which is I think it's a little

00:01:58.660 ambitious. We're going to attempt to cover two topics, frankly, each of which I think is their

00:02:05.460 own AMA. So if by the time we get through this, it's so big that it is two AMAs, the person

00:02:11.920 listening will say, what were they talking about? They just covered one topic. So as it stands at

00:02:16.240 this moment, we're going to attempt to get through both everything that has to do with fat oxidation

00:02:22.840 and fat flux and all these things you're going to explain in a second. And we're even going to

00:02:28.800 try to tackle the entire topic of nicotine. So let's, let's see if we can do it.

00:02:35.260 I feel like ambitious is the right word, but yeah, let's give it a shot.

00:02:39.240 So the first, first topic is fat flux. And we, I think a lot of questions come in about this and

00:02:45.220 there's a few variations on a theme. So I'll just, I'll summarize a few of these questions for you.

00:02:50.820 The first question is why does an oxidation of fat necessarily mean you're losing total body fat?

00:02:56.960 If I eat a low carb diet and become a quote, fat burning machine, end quote,

00:03:03.200 why don't I always lose fat on this diet? Another way of saying this too is a good question is if

00:03:08.880 I'm in ketosis, doesn't it mean I'm burning fat? And just for the record, this is, this question

00:03:13.000 came in from ketogenic man inside joke. We get this question in one form or another constantly.

00:03:23.500 So I think that's why we decided to just dedicate an entire segment to this because it's super

00:03:29.240 important and it is confusing, right? So just to be clear, let's just get the punchline out of the

00:03:35.080 way. First, you can absolutely be in ketosis and gain weight. You can absolutely be quote unquote

00:03:42.600 fat burning machine and still accumulate fat. Let's go one step further and accept the fact

00:03:53.060 that we're going to use a bit of shorthand here, which is gaining weight and gaining fat. We're going

00:03:57.080 to talk about interchangeably. Is that fair? Because I mean, when people say I want to lose weight,

00:04:02.100 what they really mean is I want to lose fat. And when people say I want to gain weight, they usually

00:04:06.920 mean I want to gain muscle. So if we can simplify this a little bit and say that people rarely want

00:04:12.840 to lose muscle and gain fat. I think it helps to think about this kind of like an engineering problem,

00:04:21.640 which is always dangerous in biology because engineering is frankly cleaner and neater than

00:04:27.860 biology. But I do think that we can simplify this problem without rendering our simplification

00:04:34.480 unhelpful and in doing so really start to understand the ins and outs of this.

00:04:40.040 So if we take the example you gave Bob, which is a person who says, hey,

00:04:43.620 I want to lose excess body fat and the approach I'm taking is a ketogenic diet or some form of low

00:04:50.720 carbohydrate diet. Does it guarantee that I'm going to lose weight? Well, again, let's break it down.

00:04:56.080 We already said the first thing is losing weight means losing fat. And now let's break that down one

00:05:00.600 step further. How do you lose fat? So broadly speaking, there would be two approaches to this.

00:05:06.100 One would be to reduce the total number of fat cells. Another way would be to shrink the fat cells. 0.67

00:05:14.220 Now the former is most typically something that is done with liposuction. So that's really the way we

00:05:20.840 lose fat cells is you cut a whole bunch of them out. By the way, there were some interesting studies

00:05:25.860 that were done a little over a decade ago. One published in the New England Journal of Medicine

00:05:31.020 that demonstrated that there was a totally different metabolic effect of those two approaches.

00:05:36.880 I don't remember the details of it, but basically one group lost a significant amount of total body

00:05:42.040 fat having the fat cut out. The other group lost it by a dietary intervention that took the same amount

00:05:49.900 of fat off. So at the end, they both had the same body composition directionally, but one had done

00:05:56.000 it through reducing the number of fat cells. One had done it by shrinking the fat cells. Can you guess

00:06:00.780 if there was a difference between them, Bob? I think there might be, although I'm tipped off because

00:06:06.580 I think it was a New England Journal of Medicine paper. It was, yeah. Sam Klein was one of the authors.

00:06:12.180 That's right. And yeah, there's a profound difference. So we should never confuse the metabolic

00:06:16.340 benefits that come from reducing the size of adipose tissue with reducing the amount of it. The

00:06:21.180 former, in the case of liposuction, is really a cosmetic procedure, whereas the latter, of course,

00:06:26.520 has cosmetic benefits, but much more importantly is a metabolic improvement. Okay. So if you accept

00:06:32.680 everything I just said, then we can simplify this problem into how do you shrink a fat cell? Is that

00:06:39.540 fair? I think so. All right. So now let's understand the fat cell. And again, let's go back to how an

00:06:48.400 engineer would think about this. An engineer would think about this by drawing a boundary around this

00:06:52.740 and looking at the boundary conditions and effectively understanding what goes in and what

00:06:58.020 comes out. Mass cannot be created from nothing and mass cannot disintegrate into nothing. So if a fat

00:07:04.760 cell gets larger, there is a net accumulation of fat in that cell relative to how much goes out of it,

00:07:12.040 and the converse is true. So again, silly example, but if you have a room and the room has a hundred

00:07:18.500 people in it, and there are people traveling in and out of the room constantly, if you want to understand

00:07:25.820 if that room is increasing or decreasing in the number of people in it, you need to understand at every

00:07:33.460 point for which there's an entry or exit what is happening. And by doing that, you can understand

00:07:39.980 what is the net increase or decrease. And I like to refer to that as flux. And I won't get into why

00:07:48.040 that's technically, that's not a perfect definition of flux, but it's sort of the way my brain works is

00:07:53.520 to sort of borrow that term from physics and basically say, look, we're going to talk about this

00:07:57.460 through the lens of fat flux. What is the flux of fatty acid substrate into and out of a fat cell?

00:08:04.480 And can we infer the behavior of that fat cell in response to that? So I guess before I go on, Bob,

00:08:11.660 I just want to make sure, anything you want to add to that? Or does that seem like a reasonable way to go

00:08:14.800 after this? A couple of things. So you alluded to it that when we talk about weight loss or weight gain or fat loss

00:08:21.240 or fat gain, a lot of times we'll hear about calories in calories out, right? The amount of

00:08:26.080 basically if more energy is entering the system than leaving it, the system is getting bigger and

00:08:30.780 vice versa. If more energy is leaving the system than entering it, it's more or less getting smaller.

00:08:37.180 And what you're talking about is at the level of the adipose tissue. So when we're talking about

00:08:40.980 how much fat is going into the adipose tissue and how much is being released and also how much is

00:08:45.360 being trapped, we'll get to, I think that's important. And the second thing too, is I'm glad that you

00:08:49.820 use the word flux because you have an amazing, I don't know if you mentioned it, but you have an

00:08:54.480 amazing blog post on this topic, which is the lessons of fat flux. And when we moved your blog

00:09:00.920 posts over to peteratiamd.com and I was privileged to adding the header images to the blog posts.

00:09:09.180 And in this case, I took the liberty of, since you used the word flux, I have a picture of the

00:09:13.140 flux capacitor and the DeLorean, which I'm sure you know that it's what makes time travel possible.

00:09:18.500 We could cover that in another episode. It's also an important concept, but those are a couple

00:09:24.700 things that I would add. If we didn't understand fat flux, there would be no flux capacitor. And

00:09:29.520 I mean, Marty might still actually be in the future, in the past. I don't even recall.

00:09:35.980 Both. Depends on which one you're watching.

00:09:37.540 Both. Depends on which version. There you go.

00:09:38.760 Okay. So let's start this discussion with a more technical look at what I'm talking about. And then

00:09:47.660 I'm going to simplify this. So Bob, you have a great figure of what's actually called white 0.89

00:09:54.820 adipose tissue or WAT. And I'll explain what that is in a moment, but if you don't mind,

00:10:00.600 can you just pull that up and share your screen so that I can see it and everybody viewing this can

00:10:06.080 also see it? Yes, it is up. Okay. A lot going on in this diagram. First, let's start by why this is

00:10:13.120 called white adipose tissue. So tissue makes sense, adipose fat, but why white? Well, white is to

00:10:18.960 contrast it from brown. So when you're talking about fat, you always want to differentiate between WAT

00:10:24.600 and BAT. At some point, we will undoubtedly do a lengthy discussion on BAT. BAT is very interesting.

00:10:31.780 It is a form of adipose tissue that is not as prevalent as WAT, but it has really unique

00:10:39.200 metabolic properties, namely a higher concentration of mitochondria and therefore a much greater

00:10:44.420 metabolic activity. Bob, you and I have spent a ton of time doing our own research on BAT as it

00:10:50.540 pertains to cold adaptation and a whole bunch of other things around that. So let's back burner that,

00:10:56.240 but I think it's worth coming back to in another episode. So what we're focusing on is what most people

00:11:00.780 think of when they think of fat, which is, again, if anyone's ever watched surgery on TV or something

00:11:06.720 like that, or had a lipoma yanked out of their arm, you can see it's a glistening yellow, relatively

00:11:14.420 acellular structure. And if you look at it under a microscope, it looks surprisingly simple. So even

00:11:21.560 though, as we now know, white adipose tissue is an endocrine organ, right? It is way more complicated

00:11:27.860 than it looks under a microscope. Under a light microscope, it looks like a bunch of nothing.

00:11:32.400 So what you see here, if you look closely, is two sides. You have an inside, and I don't mean

00:11:42.060 inside. I mean an inside, like a going into it side, and you have an outside. And again,

00:11:49.120 I don't mean an outside. I mean a going out side. So on the left-hand side of this drawing,

00:11:53.860 and by the way, if you're listening to this on audio, I would encourage you to watch it on video

00:11:58.540 or at a minimum, maybe hit pause, and now go and look at the show notes where you'll see this

00:12:03.280 diagram. But on the left-hand side of this page, you could largely think of this as having two doors.

00:12:10.820 So the upper left door and the lower left door are two ways that the fat cell gets fatter. And on

00:12:18.640 the right-hand side of this page, you have the exit door. This is how the fat cell gets skinnier.

00:12:23.400 So let's talk about each of these doors.

00:12:25.960 Thank you for listening to today's sneak peek AMA episode of The Drive. If you're interested

00:12:30.780 in hearing the complete version of this AMA, you'll want to become a member. We created a

00:12:35.400 membership program to bring you more in-depth, exclusive content without relying on paid ads.

00:12:41.660 Membership benefits are many, and beyond the complete episodes of the AMA each month,

00:12:46.280 they include the following. Ridiculously comprehensive podcast show notes that detail every topic,

00:12:52.020 paper, person, and thing we discuss on each episode of The Drive. Access to our private

00:12:57.500 podcast feed. The Qualies, which are a super short podcast, typically less than five minutes,

00:13:03.160 released every Tuesday through Friday, which highlight the best questions, topics, and tactics

00:13:07.680 discussed on previous episodes of The Drive. This is particularly important for those of you

00:13:12.780 who haven't heard all of the back episodes. It becomes a great way to go back and filter and decide

00:13:18.160 which ones you want to listen to in detail. Really steep discount codes for products I use

00:13:22.880 and believe in, but for which I don't get paid to endorse. And benefits that we continue to add

00:13:28.100 over time. If you want to learn more and access these member-only benefits, head over to

00:13:32.680 peteratiamd.com forward slash subscribe. Lastly, if you're already a member, but you're hearing this,

00:13:39.640 it means you haven't downloaded our member-only podcast feed, where you can get the full access

00:13:43.840 to the AMA and you don't have to listen to this. You can download that at peteratiamd.com forward

00:13:50.440 slash members. You can find me on Twitter, Instagram, Facebook, all with the ID peteratiamd. You can also

00:13:58.820 leave us a review on Apple Podcasts or whatever podcast player you listen on. This podcast is for

00:14:04.660 general informational purposes only and does not constitute the practice of medicine, nursing, or

00:14:09.380 other professional healthcare services, including the giving of medical advice. No doctor patient

00:14:15.360 relationship is formed. The use of this information and the materials linked to this podcast is at the

00:14:21.160 user's own risk. The content on this podcast is not intended to be a substitute for professional

00:14:26.640 medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice

00:14:34.000 from any medical condition they have, and they should seek the assistance of their healthcare

00:14:38.600 professionals for any such conditions. Finally, I take conflicts of interest very seriously. For all

00:14:45.180 of my disclosures and the companies I invest in or advise, please visit peteratiamd.com forward slash

00:14:52.600 about where I keep an up-to-date and active list of such companies.

00:15:08.600 Thank you.

00:15:09.600 Thank you.

The Peter Attia Drive - April 12, 2021

#157 - AMA #22： Losing fat and gaining fat： the lessons of fat flux

Episode Stats

Summary

Transcript