The Peter Attia Drive - #173 - AMA #26： Continuous glucose monitors, zone 2 training, and a framework for interventions

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

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

00:00:39.220 Welcome to ask me anything episode 26. I'm once again joined by Bob Kaplan. In today's episode,

00:00:46.540 we field a bunch of questions that are kind of follow-up questions to topics we've

00:00:51.480 recently done deep dives into. The two main themes are more follow-up on CGM and more follow-up on

00:01:00.440 zone two. Now, when Bob first told me that those were going to be two of the things we're going to

00:01:04.920 talk about, my first thought was, we have nothing else to say on these topics. We have spent so much

00:01:09.380 time on them, but it turned out I was wrong. There were a lot of really good questions here

00:01:13.260 and things I hadn't considered. So if you find yourself wanting on either of those topics,

00:01:18.280 this episode is definitely for you. If you think you know everything on those,

00:01:22.200 it's probably still for you. The time of the recording here was in the middle of the Tour de

00:01:26.340 France. So we had a little digression on performance physiology and cycling. Now, remember if you're a 0.99

00:01:31.900 subscriber and you want to watch the full video of the podcast, you can find it on the show notes page.

00:01:37.160 If you're not a subscriber, you can watch a sneak peek of this video on our YouTube page.

00:01:41.440 So without further delay, I hope you'll enjoy AMA 26.

00:01:48.280 Hello, Peter.

00:01:52.440 Hey, Bob. How are you, man?

00:01:54.960 I'm doing well. How are you?

00:01:56.600 I'm great.

00:01:57.640 Okay. You ready for an AMA?

00:01:59.480 I am. I saw the agenda. It's very aggressive.

00:02:03.580 Yep. That's how I like it.

00:02:05.500 Ambitious.

00:02:06.720 Yes. Yeah. To say the least. I don't know if we'll get through everything,

00:02:10.460 but we did get a lot of follow-up questions on CGM based on our previous, actually, I think it was

00:02:18.840 the previous AMA where we talked about glucose. We talked about mean glucose, glucose variability,

00:02:23.660 and glucose spikes. And then we also had that Sunday email on CGM and non-diabetics. It was

00:02:30.800 related to a JAMA perspective talking about it. So there's a bunch of questions on that.

00:02:35.460 Okay.

00:02:36.380 We also have a couple of questions on Aura, the sleep wearable, the Aura ring. We've got some

00:02:43.820 exercise-related questions, and we may work in one or two additional questions if we have time.

00:02:49.380 How does that sound?

00:02:50.960 I think it sounds like a good list.

00:02:52.860 Okay. So Peter, since we have a lot of these CGM-related questions, one of the things that

00:02:59.320 I've heard you talk about is you have a framework for interventions that I think will be really

00:03:03.300 helpful in laying the foundation for how you think about CGM and their use in different

00:03:08.920 populations. So can you start off by telling us a little bit about that framework?

00:03:14.180 Yeah. So again, it doesn't pertain to CGM specifically. It pertains to anything

00:03:19.440 that comes across my plate. And the first time I actually contemplated this was really when I

00:03:25.780 started trying to look critically at the data around meditation. So this was probably about

00:03:31.280 maybe eight to 10 years ago. But anyway, it basically asks a series of questions. So the

00:03:36.320 first question is, what is the risk of harm from doing this thing? That's a direct question. So if you

00:03:42.580 do X, how high is the probability of harm? The second question is obviously the contrapositive

00:03:50.540 of that. If you do X, what is the probability of benefit? And then the third question, and by the

00:03:59.320 way, before I go to the third question, those first two questions are so obvious that they're almost not

00:04:04.060 worth stating. And of course that's mirrored in the way the FDA organizes drug trials, right? So a drug

00:04:10.960 trial is organized first by, well, after you get through the preclinical data, the animal work,

00:04:17.060 you know, after the IND has been filed, your first trial in humans, which is called a phase one trial

00:04:21.980 is looking at harm. I mean, it's typically a small trial with dose escalation that is only trying to

00:04:30.760 understand if as you escalate the dose, do you see an increase in side effects? Very occasionally,

00:04:37.500 you see some benefits in a phase one trial. And if you do, that's interesting, but you generally

00:04:42.100 can't take it to the bank because the study is so small and generally it's quite homogeneous.

00:04:47.600 So that's when you move on to phase two studies, which are geared towards efficacy, i.e. is this thing

00:04:53.360 doing good? And of course, if the phase two trial is positive, you move to a much larger trial called

00:05:00.280 a phase three trial, which really doubles down on efficacy. Of course, both of these trials will

00:05:06.040 continue to be able to pick up any signal of harm. So you're always in the spirit of trying to capture

00:05:11.060 that. But the real point here is you're raising the bar, so to speak, for what you're demanding of

00:05:16.880 this. So again, what's the risk of harm? What's the probability of benefit are two obvious questions.

00:05:22.640 I think the third question then is what's the opportunity cost of this intervention? And I feel

00:05:29.220 like I've talked about this on a previous podcast before, and maybe it was even one of ours, but

00:05:32.660 there was this device, sort of a device that you would listen to and it would supposedly put you

00:05:40.520 in a trance. And the company that was proposing this thing had all sorts of theoretical benefits

00:05:47.160 from using it. If you listen to this device, you were less likely to get breast cancer and all of

00:05:52.780 these other things. So was there any harm in this device? As far as I could tell, no, I really didn't

00:05:59.760 think that listening to this device was harmful in any way. Was there any benefit of this device?

00:06:08.060 Certainly not to the extent that they made claims. That said, I had tried the device because a friend

00:06:14.180 of mine bought it for me. And I have to admit, it was the most relaxing thing I'd ever done. In fact,

00:06:19.360 virtually every time I tried it, I fell asleep. So maybe there was some good in that. Maybe there was

00:06:24.060 some bad in that if it was a daytime nap and you could speak to the disadvantages of daytime napping,

00:06:29.580 but there was an opportunity cost to it. And I don't just mean financial. So the device was

00:06:34.120 pretty expensive. I want to say it was like a thousand bucks if you were going to buy the thing.

00:06:38.580 Well, a thousand bucks is no trivial sum of money for anyone. So that's obviously something that has

00:06:44.360 to be weighed against what else could be done with an opportunity cost. But the other thing you have

00:06:48.620 to keep in mind is their prescription for use was two 20 minute sessions a day, much along the lines

00:06:55.220 of like transcendental meditation, which is similar, but has much better data. And that's where I kind

00:07:01.700 of thought, well, there's a problem because for most people who are super busy, 40 minutes a day

00:07:07.200 for very questionable benefit didn't make a lot of sense if it came at the expense of other things that

00:07:16.680 undoubtedly had benefit such as, could that be 40 minutes a day of actual meditation? Could that be

00:07:23.900 40 additional minutes a day of sleep? Could that be 40 minutes a day of exercise? All things that I

00:07:29.600 would point to as having far greater evidence in favor of. So I think anytime you're thinking about

00:07:36.620 doing something, you want to kind of go through that. And those are especially important questions to

00:07:43.940 be asking when the answer is not readily apparent from RCTs that have generally already answered

00:07:52.400 one and two. Now remember, many RCTs are the easiest RCTs to do are the ones that are based on

00:07:58.980 pharmacology. And they're generally addressing one and two, but they're not really addressing three

00:08:04.680 because there really isn't much of an opportunity cost to taking a pill outside of the economic cost.

00:08:09.360 But the time cost of it is relatively low. Of course, when it comes to RCTs that are more

00:08:15.620 intervention-based, such as exercise, yes, you want to be able to think about this. But as you look to

00:08:21.420 something like CGM in the case of non-diabetics, this framework to me is very helpful because at this

00:08:28.780 time, we don't have great RCTs to point to that say in people who are not yet diabetic, there is a

00:08:36.240 benefit to using CGM. So again, as you go through that, you ask yourself the question, what is the

00:08:41.740 risk of harm? And again, when we talk about CGM specifically, I think the risk of harm is very low.

00:08:48.720 If we were going to speculate what could be harmful about it, well, I think the most obvious thing that

00:08:53.320 comes to my mind is anxiety that it can stoke, right? It can create obsession in someone. And

00:09:00.040 certainly I can speak to that personally. I don't think personally I've found it harmful,

00:09:05.020 but I could absolutely understand it. And I frankly think we have some patients in whom

00:09:10.380 I've never recommended it. So for example, we have some patients who have a history of eating

00:09:15.200 disorders. These are patients I would not in any way, shape or form advocate the use of CGM.

00:09:21.620 I think it's yet another tool that can create a negative cycle around obsession. Is there any chance

00:09:29.220 of it doing good? Well, I mean, I think I've already made the case for that. I think there's ample

00:09:33.200 chance for it doing good on two fronts, right? The first front is what I call insight-based good,

00:09:40.740 which is teaching you what your carbohydrate tolerance is. That's what the tool is for.

00:09:47.280 And then secondly, what I would call behavioral good or behavior modification, which is effectively

00:09:53.380 a strapped on version of the Hawthorne effect. So when you're wearing a CGM, you're basically

00:09:59.420 utilizing a tool that is monitoring you. And there is no shortage of data to support the idea that when

00:10:05.940 people are asked to monitor food intake, they make changes in the right direction. So if I said to you,

00:10:13.040 Bob, I want you to record everything you eat for the next month and track it in a food diary,

00:10:20.320 are you going to make better food choices than you are making now? And the answer is unequivocally,

00:10:25.820 yes, you are going to do that. Which is also not to pile on, I guess this is the first time I'm

00:10:31.740 mentioning observational epidemiology so far, at least for this episode. But that's one of the

00:10:36.620 challenges right there with food frequency questionnaires is that they start asking them

00:10:41.320 to ask them what foods they're eating or they ask them what foods they ate. And oftentimes just that

00:10:46.820 by asking, they're changing their behavior. And so you're not really getting an accurate

00:10:50.860 representation of what they ate previously. Right. So that's a problem that plagues epidemiology,

00:10:56.580 but you can use that to your advantage. Right. So, you know, and we do that stuff clinically,

00:11:01.660 right? This is how you create accountability for patients. You say, look, we're going to check in

00:11:07.220 once a day and I just want you to tell me what you ate. And, and, and even if you provide no other

00:11:14.640 instruction, which is, oh, I want you to have this many grams of protein and this many grams of carbs

00:11:18.880 and this many grams of fat. No, no. Even if you don't go to that level, if you just say, I just

00:11:22.420 want you to tell me what you ate, that level of accountability immediately changes a person's

00:11:26.780 behavior. And that's an example of how you can use that to your benefit. I guess I'll get to the third

00:11:31.720 point, which is opportunity costs. So what's the opportunity cost of one of these devices? Well,

00:11:36.480 I think hands down the biggest opportunity cost is the economic cost. These things are not cheap.

00:11:42.200 And if you are not diabetic, you are not going to have your insurance company cover one of these

00:11:46.820 devices. So there are no shortage of companies out there that are repurposing and repackaging

00:11:53.620 CGM. So there are really three companies that make CGMs in the clinical grade. So there's Medtronic,

00:12:01.620 Abbott and Dexcom. And again, by way of full disclosure, I consult with Dexcom, not on their CGM

00:12:08.960 business, but actually on a part of their business that deals with other analytes. So other things that

00:12:14.340 you could measure. So I actually don't really interact much on the CGM side, but those three

00:12:19.640 companies make CGMs. And then there are lots of companies like Levels and Super Sapiens that people

00:12:25.700 have heard of who are plugging in those CGMs into their apps to help users with their goals, be it

00:12:32.380 weight loss or otherwise. Well, they're not cheap. I'm trying to remember what the cost is. The monthly,

00:12:38.720 I mean, I feel like the daily cost of CGM is about 10 bucks and there's probably cheaper ways to get

00:12:44.020 it if you're buying your CGM on eBay or if it's a little bit expired, but directionally speaking,

00:12:48.420 it's about a $10 a day habit. That adds up, right? But that's, you know, call it $3,500 a year. That's

00:12:54.520 a huge expense, assuming you need it every minute of every day. And I don't think you do. I think you

00:12:59.640 can gain a lot of insight using these things periodically. I don't think this is something you

00:13:03.560 need to be tethered to every minute of every day. There are some people like me who enjoy that.

00:13:08.200 Not going to lie. I've been wearing CGM for almost six years. It never gets old to me. I continue to

00:13:14.720 find insights that just provide value. And more than anything else, it's really the behavioral

00:13:20.840 tool. And that might make me a mental midget. I might just be a guy that is such a simple plebe 0.99

00:13:26.840 that having that little CGM on my arm is what keeps me away from the ice cream in the freezer,

00:13:31.900 in the cookies, in the pantry. But if you saw my freezer and you saw my pantry, you would certainly

00:13:36.140 understand why I stand to benefit from using CGM. I think you mentioned this in the article or the

00:13:42.980 Sunday post about how the percentages change with when you talk about how much insight you're getting,

00:13:49.660 say, in the first 30 days versus long-term, whether it's a motivational or a behavioral tool

00:13:54.620 and how those can shift. But I also want to mention that when I was at UVM, I was getting my undergrad and I

00:13:59.920 was studying nutrition that, to your point about ice cream in the freezer, I remember for one of our

00:14:06.300 courses that we were taking, we started doing a food log or a food diary. And I remember at the

00:14:10.160 time I was eating, I don't know why I got into this, but actually you probably will know why.

00:14:14.780 I was eating a pint of Ben and Jerry's chocolate chip cookie dough, just religiously.

00:14:19.220 Is a pint the one that's this big? Like the little one? Is that a pint?

00:14:23.260 That's the 16-ouncer. Yeah. But I think that's the only thing that Ben and Jerry's comes in.

00:14:29.240 Okay. Okay. And you were eating one of those a day?

00:14:31.240 I was eating one of those a day after dinner and it was just like a, yeah, whatever kind of habit.

00:14:37.200 Then I was doing the food log and I had to keep a food log. And that's how I kicked that. If you

00:14:42.780 want to call it a habit, that's how I kicked the Ben and Jerry's habit. I said, look, I'm going to

00:14:45.600 have to write, you know, for the, I think it's two days during the week and one day during the

00:14:49.660 weekend that I had to do it. And that's, I think, typically what they do for food diaries. And you

00:14:53.440 just log everything you eat, you know, real time over 24 hours for like a Monday and a Thursday and

00:14:58.420 a Saturday. And I remember I, I kicked that habit, but it just, it reminds me of this stuff that

00:15:03.980 some of these things are behavioral tools, maybe in disguise. But I think you mentioned something

00:15:09.600 like 90, 10 at the beginning with your. Yeah. Yeah. And that, that's sort of what I tell patients.

00:15:13.720 Cause look, a lot of our patients are like, Hey Peter, what do you think? I mean, do you,

00:15:17.080 do you think I should do this? And my answer for most of them is, yeah, I think you should.

00:15:20.040 I think everybody deserves a three month trial of CGM. Again, notwithstanding a handful of patients

00:15:25.000 who I think have contraindications. And I typically say, look, it's going to start out as about 90,

00:15:31.440 10, 90% of this is going to be insight. Like you're going to be going, Holy cow. I can't believe

00:15:38.360 fill in the blank. And only 10% of it is going to be changing your behavior through this Hawthorne effect.

00:15:45.000 I said, by the end of that 90 days, that's going to flip again. It depends on how much

00:15:50.500 insight you look to extract, but directionally within about three months, you're going to be

00:15:56.240 like, you know what? I've sort of figured out the effect of grapes and the difference between like

00:16:01.300 a grapefruit and a banana. Like I've, I've kind of got that dialed. And I've also figured out that

00:16:06.800 I can eat a ton of carbs after I work out. But if I eat a ton of carbs before bed,

00:16:12.140 totally different effect on my blood glucose and over the overnight and in the morning,

00:16:16.620 but the shift is you start to gamify it a little bit. So yeah, I guess that's sort of what I would

00:16:23.540 say on, on my framework for how to think about these things. Okay. So a related question to CGM.

00:16:31.060 I've got, actually, you just mentioned grapes. So this, this person says, my glucose spikes when I

00:16:34.740 eat some fruits, but not others. Do you know why this happens? And does it mean that I should

00:16:38.860 avoid fruits that spike my glucose? Thank you for listening to today's sneak peek AMA episode of

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The Peter Attia Drive - August 23, 2021

#173 - AMA #26： Continuous glucose monitors, zone 2 training, and a framework for interventions

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