Personalized Nutrition Part 3: Zoe and Metabolic Response Testing


In the final installment of this three-part series we’re digging into the world of metabolic response testing. Currently, there seems to be increasing emphasis on the importance of understanding your unique response to macronutrients, especially carbs and fat. Companies like Zoe are encouraging everyone to wear continuous glucose monitors (CGMs) while influencers like the Glucose Goddess are extolling the virtues of flattening your glucose curve. But is personalized metabolic response testing necessary for everyone? And do these expensive programs lead to clinically significant health improvements? Join us, two Registered Dietitians, as we explore these questions (and more) in this look at personalized metabolic response testing. 

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Episode Transcript

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Welcome to Nutrition For Mortals, the podcast that says life is too damn short to spend your time and attention worrying about your food choices.

So let's take a deep breath, and then join us, two registered dietitians and friends, as we explore the world of nutrition with a special focus on cultivating a healthy and peaceful relationship with food.

My name is Matt Priven, and I am joined as always by my co-host, the best dietitian on planet Earth, Jen Baum.

Hey, Jen.

Hey, Matt.

And just a quick reminder, if you would like to support the show, we do have a Patreon, where we do an extra bonus episode every month.

A portion of our Patreon goes to support the Hunger Project, which is a wonderful organization.

And a reminder, we are real live dietitians in practice.

And so if you or anyone you know has ever thought about or been interested in working with a dietitian, you can always reach out to us.

And we're online at oceansidenutrition.com.

So Matt, this is the last in our personalized nutrition series.

And I feel like I've learned so much.

We were joined by the amazing Dr. Lara Hyde for our first two episodes.

And I'm just gonna shout her out again and say thank you so much, Lara, for joining us for our first two conversations.

Because like I said, I think she brought a perspective that was really unique and helped me learn.

Yes, thank you, Lara.

You're the coolest.

Okay, so let's set up this episode today because today we are talking about metabolic response testing.

So as I've said now two other times, everything in healthcare right now is shifting towards this hyper personalization.

Medicine's all about precision medicine and nutrition's no different.

And the big bet that a lot of companies are making is that we're gonna see this shift from generalized nutrition recommendations to individual personalized nutrition recommendations.

So as a recap, in episode one, we looked at some of the personalized nutrition offerings that focus on the gut microbiome.

In episode two, we turned our attention to nutrigenetics and trying to quote unquote eat for your genes.

And now we've arrived at personalized nutrition based on your metabolic responses to foods.

Well, and maybe we should start this one with talking about or defining what we actually mean by metabolic responses.

Absolutely.

Well, basically, we just mean, what are we doing with the food that we eat?

How are we responding in our blood and at a cellular level to those foods that we take in?

So should I give you an example?

Yeah, definitely.

Okay, so say you eat a potato, right?

I love potatoes.

So potatoes are a source of starch, a carbohydrate.

And when we eat that potato, it gets broken down during digestion.

It's absorbed into our bloodstream, which leads to our blood sugar level rising.

And when we're trying to understand personalized metabolic responses, we start asking questions like, how did your blood sugar rise compared to someone else who also ate a potato?

Yeah, exactly.

I mean, I always think of it as like, essentially we're talking about how our own specific personal body responds to the foods that we eat.

Yeah, and we're trying to extrapolate to health outcomes and say, what can we glean from how you respond that might tell us something about where you're going with your health and how that might dictate what you might want to focus on with your nutrition.

So that's the idea.

And this applies especially to, like I said, carbohydrates and also dietary fat.

Those are some of the big areas that we tend to look at in personalized nutrition for metabolic responses.

Well, and this I think leads to the question of what are specifically some of the types of personalized nutrition offerings that focus specifically on metabolic responses?

Yeah, okay, great question.

So really, we're going to set up the episode now, like what are we going to dig into?

And so there's two big categories that I want to focus on today.

The first has to do with your blood sugar levels, but more specifically, if we look at the market now, there are companies that are really encouraging people to be very in touch with understanding the rises and falls of their blood sugar.

And so what we see now are companies that are selling continuous glucose monitors to the general population.

Yeah, this is something I'm seeing a huge increase in in the individuals I'm working with, specifically people asking me the question, if I don't have prediabetes or diabetes, are there benefits to me using a continuous glucose monitor?

Same, and I see this online all the time too.

There's ads for companies that are selling continuous glucose monitors, but not only the device itself, which we can describe more in a minute, but also flashy apps that pair with that monitor that try to guide your eating decisions and what you should or shouldn't be doing with food.

So definitely something we need to talk about.

Yeah, and I think you nailed it.

The template seems to be companies that sell the device itself.

And there's typically an algorithm then dictating or spitting out food recommendations based on continuous glucose monitoring data for an individual.

Right, exactly.

So that's the first big bucket we'll talk about is continuous glucose monitors or CGMs.

And the other one is products that are based around metabolic tolerance testing.

So really what we're talking about here is the company Zoe.

So are you familiar with Zoe, Jen?

Yes, yes, I have seen Zoe.

I have gone on their website.

I have read their blog.

I think, aren't we all aware of Zoe at this point?

I think a lot of people are.

It's a big name in the space of personalized nutrition.

If we got through this trilogy of episodes without mentioning Zoe, we would have absolutely missed something.

And so what they're doing is tolerance testing.

And so with Zoe, you're testing your tolerance to carbohydrates and your tolerance to dietary fat.

And then they're giving you recommendations in their app that are supposed to be personalized based on how well you tolerated a test meal.

And so we'll get into the specifics of that later, but we have a lot to say, and there's actually some interesting research we can dig into when we get to Zoe.

And this is interesting too, because it's the only test right now that's like, you know, widely available that offers blood fat testing.

So it's testing your tolerance to dietary fat, looking at your blood and seeing how are you managing or handling that fat that you're taking in.

So a lot to talk about there.

Right, and so really the two categories we're going to focus on today are companies that are, you know, marketing and selling CGMs.

We have Zoe, which is kind of in its own category.

I'm going to throw out honorable mention to the metabolism vape Lumen, which I know we're not going to talk about today because we already talked about Lumen on a previous episode, but they are also kind of doing their own thing in this metabolic response space.

Yes, exactly.

They're doing a sort of indirect calorimetry on the go metabolism vape thing that we did talk about in the past, so we won't cover that today, but I think we have plenty to talk about just focusing on those first two categories.

Yeah, for sure.

Okay, so maybe the best thing to do is start with talking about companies that are specifically selling marketing CGMs, but I think before we do that, can we talk a little bit about CGMs, continuous glucose monitors in general, and just, come on, I don't know, do an overview on how they work, what information they can tell us, and all that good stuff?

Yeah, that's very wise.

So yeah, continuous glucose monitors, we'll call them CGMs from here on out, just because it's a lot less to say.

But speaking objectively, very cool technology, very important, very cool technology.

For years, folks who wanted to know their blood sugar, what would they do?

They prick their finger with a little lancet, they gather some blood and they drop it on to a test strip that went into a little handheld device.

And so obviously, if you wanted to know your blood sugar every hour, you'd spend a lot of time bleeding.

It was a big process, right?

And then CGMs came along and they kind of changed the game.

So a CGM is a sensor that you wear on your body.

It has this little filament that goes into your skin, pokes down into the interstitial fluid, and so it can read your blood sugar, your blood glucose levels, many, many times throughout the day.

And these pair with an app on your phone now, where if you want to know your blood sugar, you just open the app, you boop it against the sensor, wherever it is on your body, typically on the back of your arm, and it shows you your blood sugar on the app.

So this gives people the opportunity to see more detailed graphs of the up and downs of their blood sugar throughout the day.

Exactly.

Yeah, that's a great overview.

And I think an important point that you made, or an important detail, is that CGMs are monitoring the interstitial space that is essentially the fluid between cells.

So it's not measuring your blood glucose exactly, but we have kind of found that interstitial fluid and blood glucose tend to be correlated to each other pretty strongly.

Yes, exactly.

And so I think as we kind of get into the modern offerings in this personalized nutrition space, there's a couple of important things that we want to lay out first.

I think that we should say about CGMs and their importance in people's lives.

So do you agree with that?

Yeah, let's talk about our gratitude for CGMs first and foremost.

Yeah, so I think we're on the same page here.

Again, this is important technology.

It can be very useful for people with diabetes and some other health conditions.

And there's a discussion to be had about, is it a lifelong device for certain people, even with diabetes?

That's open for discussion and very individual, but it is important technology nonetheless.

Yeah, for sure.

And I think there are some things that we can kind of confidently say about metabolic response.

I mean, I think there's a lot of data that really supports the idea that having consistently high blood glucose levels or very high glucose spikes after you eat is associated with the development of insulin resistance or type 2 diabetes or increased inflammation.

And so, you know, that is something that's really supported in the literature.

Yeah, that's a really important point.

We're not trying to make the case here that blood sugar curves are insignificant or unimportant for anybody, but we're really trying to get into an understanding of how people should feel about the current offerings that are being marketed to the general population to wear a CGM.

In many cases, companies saying, where's CGM?

All the time and constantly check a little app to see how you're doing.

So that's the theme.

Yeah, I think the goal here is to try to answer the question, is a CGM necessary for the average person?

So somebody who doesn't necessarily have pre-diabetes, diabetes, are there benefits?

Are there in health marker improvements that seem to be a consequence of constantly wearing a CGM?

Yes, perfectly said.

So Matt, maybe you can give us an example of one of the companies that may be pretty big in the CGM space right now.

Yeah, there are a couple.

The big one I would say is levels, all caps, levels.

Exclamation point.

And then there's Nutrisense, there's Ultra Human, there's a bunch of these companies that have popped up.

And essentially what they're doing is they're reselling continuous glucose monitors.

And what I mean by that is we don't really have many different companies making these CGMs.

We really just have two companies.

We have one that's called the Dexcom and one that's called the Freestyle Libre.

And these companies like Levels and Nutrisense, they're just reselling these CGMs with their app under their new business name.

And Levels is kind of the one that we can kind of dig into today.

Well, that's fascinating.

And my guess is that's something that maybe most people didn't know, that these companies aren't necessarily, these companies like Levels and Nutrisense, they're not developing this technology.

They're essentially just repackaging it.

Yes, exactly.

They're putting their own branding on something that is really just medical equipment that's been around for a while.

Well, and how are these companies marketing their programs?

Well, they're definitely leaning into the importance of being hyper aware of your blood sugar at all times, or quote unquote, flattening the curve.

That's a big phrase in this world.

And these companies like Levels, for example, tend to in their marketing partner with other doctors and spokespeople.

So Levels has this big team of doctors that they partner with.

And it's some people who have been topics on the show before.

So if you go to the Levels website, you see Mark Hyman and Robert Lustig and Sarah Gottfried and all these people who we've played clips of in the past, giving advice that I think in those three examples, we did not agree with.

But they're big names in the space.

And so they're players, and I'm assuming have some financial buy-in to these companies as well.

Okay, so they are definitely leaning very heavily on, we have experts that are supporting the use of our product.

And my guess is because, you and I have talked many times about other similar wellness companies, that they are making huge grandiose promises about how their product can improve your health and your life and everything, essentially.

Everything, everything is the right way to say it.

Yeah, so yeah, let me come back to your question about the promises being made.

In fact, let's play a clip from social media that came directly from levels about the importance of monitoring your metabolic health with their continuous glucose monitors that they are reselling.

Let's do it.

If you wake up in the morning, you're like, I don't feel 1000% energetic, happy, alive, the way you want, ready to just go out and live your highest truth, then you should probably dig into your metabolic health.

I mean, even people who are feeling that way should dig into their metabolic health.

But it's like, if you think about that framework that we just talked about of like this root, this trunk of the tree of so many things, like we all need to know where we stand on that.

The first order issue in the body is, is it powered?

Is it plugged in?

And so everyone needs to know that.

But if you do have symptoms, fatigue, any of the things we talked about, really in any system of the body, this is an area to dig into.

This is awesome.

If you're not 100% living your highest-

A thousand percent.

That's right.

You're not feeling a thousand percent and living your highest truth, then you need to understand your blood sugar.

That is probably the most grandiose claim I've ever heard.

So clear.

I mean, she could not have made it, by the way, this is Dr.

Casey Means, could not have made it any more clear that they want everyone to be using a CGM.

And so, that's what sets this conversation apart from the classic, like maybe if you have diabetes, you might choose to try a CGM for a period of time.

Now we're talking about everybody.

And then, and isn't it like amazing how the language they use, it really does draw you in, because I even found myself being like, well, I want to live my highest truth.

Like that sounds lovely.

Have I ever been 1000% happy before?

Never, I mean, I have never woken up feeling 1000%.

And that sounds incredible.

How do you even judge your own happiness?

That's a separate podcast entirely, but we're getting the vibe here from these companies.

And now maybe we should talk about what actually are they selling and how much does it cost, right?

Yes, I would love to know that, because that is something that I have never really looked into before.

I'm guessing it's pretty pricey.

But again, I have no idea like how much it costs to purchase a level subscription, for example.

Yeah, and you're right.

It's a subscription service.

And so what you're buying is the use of a CGM and a CGM lasts 10 to 14 days, the sensor does.

And so if you want to continuously use a continuous glucose monitor, you're reapplying a CGM sensor twice a month typically.

And so you're buying two CGMs a month on an ongoing basis.

And you're paying for the subscription to their app.

So when I went on their website and pretended to place an order for their product, I was presented with a payment screen for $506 with an ongoing $200 a month subscription.

So that's what this thing costs.

That is a ton of money.

I mean, that means that if someone was going to use a CGM for a year, it would be thousands of dollars between the monthly subscription and then also having to pay to replace the CGM every two weeks.

Yes, exactly.

And I'll say you could do a shorter term use of the CGM, but really the marketing for these companies, especially levels is like, you're going to get the most benefit if you're continuously using our product in our app, right?

And so they want to pull you into their ecosystem because it's a business that's trying to make a ton of money.

Yeah, totally.

And I think we should dig in a little bit more to the science we have around, again, whether or not it is beneficial for someone who doesn't have an impaired glucose tolerance to be using one of these devices in an ongoing way.

Right, folks without diabetes, do they need CGMs?

And I know if you've looked at the literature like I have, there ain't a ton of it, right?

Yeah, I mean, when I have looked at the literature and kind of read about this, I have seen things like validation studies.

So where they're actually just trying to get an understanding of what the glucose curves look like for individuals without pre-diabetes and diabetes.

And those studies seem to find that on average, people spend about 93, 99% of their time within the kind of normal glucose range.

I've also seen studies that really kind of throw out the idea of a glycemic index.

And what I mean by that is for a while, the thinking was that every single food would impact people's blood sugar the same.

So if I ate a potato and you ate a potato, Matt, the blood sugar curve in both of us would look exactly the same.

And that we really know that that's pretty outdated.

What we have in terms of data shows that people do respond differently to different meals and to different food items.

And so I have seen all of that science, but what I haven't seen or haven't found are things like randomized controlled trials showing that when individuals, again, without diabetes or pre-diabetes use a CGM long-term, there are improved health outcomes.

And that's a really big missing puzzle piece, in my opinion.

Yes, that research does not exist at this time, but you make a really good point.

The promise is here.

There's like a kernel of truth, as always, where there is a difference between people's responses to different foods and types of eating styles that's going to be very interesting to learn about, but is the intervention that we need constantly using a CGM, we don't have the research to support that yet.

But again, it doesn't stop companies like Levels from saying, no, we're really confident in this.

And not only that, setting the lines for where they think is the quote unquote optimal spike in your blood sugar that's going to protect you from disease.

And that gets really tricky when people start, you know, having this app on their phone, looking at it all the time, and maybe worrying about a spike that goes higher than where Levels says it should go.

Because what we don't know is, is that relevant to your health at this time?

How is that relevant for you individually?

And so there's still a lot to learn here.

But maybe we could talk a little bit about some of this discourse around blood sugar spikes, because it seems to be kind of ever present recently.

It seems to be a real theme, especially with folks like the Glucose Goddess, who are online really worrying people about spikes in their blood sugar with maybe good intention.

But I think what you and I see is people who are very worried about spikes in their blood sugar without an understanding of its relevance to their health.

Yes, exactly.

And I think you make a great point about these specific cutoff values that companies are giving people, and that honestly, I've heard the Glucose Goddess throw out there.

And my reading of the literature is that we just don't have enough data to support these very exact numbers or cutoff values that are being thrown around.

Yeah, so for a company like Levels, they're setting the lines here.

And Levels is really trying to encourage that people's blood sugar doesn't rise above 110 milligrams per deciliter after eating, and doesn't ever spike more than 30 milligrams per deciliter from where it was before eating.

So I know that's really specific numbers to call out, but they're just picking those numbers.

They're looking at the research that we have into those people who are non-diabetics, who are testing their blood sugar after eating, and they're saying, well, the average might be 135 milligrams per deciliter, but we think that's too high, because there's high rates of diabetes.

So we're going to drop that down to 110, and really make people focus on very tight blood sugar management, which is that important is the question.

Well, and what always concerns me is when we have data, and then people just choose to round down.

It kind of reminds me of like choosing BMI cutoffs on the curve you described in our BMI episode.

It seems very arbitrary and not necessarily data driven.

This word optimal compared to average leaves a big gulf that people can cross with a lot of just speculation and sort of arbitrary cutoffs.

And so these figures get shared a lot of times and kind of get energy behind them.

And so especially that's true with this idea of wanting your blood sugar to not rise more than 30 milligrams per deciliter.

And that number gets shared a lot.

And so maybe we could listen to a clip of the Glucose Goddess talking about this.

Oh yeah, let's do it.

“A spike this high, so a spike of more than 30 milligrams per deciliter after eating increases inflammation in the body.

It increases your risk of heart disease.

It increases glycation, which is aging.

And it increases your risk of developing type 2 diabetes.

These spikes accumulate over time and create pre-diabetes or type 2 diabetes.

And there's other symptoms as well that they create, like cravings, fatigue, being hungry all the time.

They can create hormonal issues in your body.

They can impact your sleep and so much more.”

What do you think about that, Jen?

It's interesting.

I'm torn on Glucose Goddess because I have watched videos of her before where she says lots of things that I agree with and that I think are backed by science and that I think could be really helpful for someone who has pre-diabetes or PCOS or diabetes.

In this case, my problem with this clip is that specific 30 milligram per deciliter number that she's throwing out there and very focused on.

Because again, as we've been talking about, there's not necessarily great science to support that that is the number.

Yeah, she seems super confident in this number of 30 milligrams per deciliter, but we just don't have the research to get that specific with at what point does a glucose spike for everybody?

She's addressing the larger population here, regardless of your health history.

At what point is that concerning?

We just don't know yet.

So in my feeling is it's irresponsible to worry people about that specific number, especially when you're also selling a supplement called anti-spike, right?

Where you're trying to make sure that people are not spiking their blood sugar too high by selling them a supplement.

I think that there's a lot to consider here that makes me really wary of this, even if some of the other stuff she says is pretty cool.

For sure.

And I think the other thing that we haven't yet brought into this conversation is the fact that there are a lot of things that affect our blood sugar and our blood glucose.

So exercise for sure, physical activity, movement, that is definitely going to impact somebody's blood sugar.

Stress, sleep.

Yeah, I think stress is a really good example, right?

Because I think we undersell the role of stress in blood sugar management.

And so if being more relaxed by not worrying about your blood sugar helps with a five milligram per deciliter difference, that could be the difference between crossing that 30 milligram per deciliter threshold anyway.

So like we have to take into account the other factors that are at play here.

And yeah, movement is a huge one.

So taking a nice walk after eating is gonna dramatically change your metabolic response to food.

Yeah, it goes to this idea of that, in many cases, I think that yes, knowledge is power, but then if that knowledge is either redundant or even potentially inaccurate or not necessarily based on the best data, then that information definitely has the potential to do more harm than good, particularly for folks that may have the inclination to get hyperfixated or hyperfocussed on numbers or food choices, right?

Individuals that fall into that category.

Yes, definitely.

I think that's good to point out, but that's more people than we realize, right?

Like there's not this hard line between people who can perfectly manage these strict recommendations and those who can't.

It's a spectrum and people move along that spectrum.

So sometimes, you know, you could have somebody who's like, my relationship with food is great.

I do not hyperfixate on things.

And then they get a CGM on their arm and suddenly they're really worried all the time.

And so that is something to keep in mind.

Absolutely.

Yeah, the other thing to say too, is you can flatten your blood sugar curve with really unhealthy behaviors, right?

And so this isn't like, you know, as long as you can get this curve to come down, then you're crushing it.

Like you could do some things that are kind of not healthy to make that happen.

Like what?

Let's give some examples.

Okay, you could get really drunk.

That would flatten the curve.

I mean, the research has shown us that drinking alcohol actually attenuates the rise and fall of your blood sugar.

So, you know, that's an example of an unhealthy way to flatten the curve.

Another would be, and the more common one, I think would be people who try to flatten the curve by really just avoiding carbohydrates, right?

So you can get a pretty flat line if you eat a keto diet, but do we recommend missing out on this important macronutrient we need for energy, carbohydrates?

No, absolutely not.

And so there's lots of ways to get here that don't really result in a healthier, balanced way of eating.

Yeah, that's such a great thing to point out.

Yeah, so we'll do more discussion towards the end of the episode, but let's dig into Zoe now.

Are you ready?

I am, and I am particularly excited to talk about this because you did the Zoe program.

I did, I did.

How have I not said that up to this point in the episode?

But yes, to prepare to talk about this, Zoe's kind of complicated, there's a lot going on.

And so I said, I'm gonna get my hands dirty here and do this program and see what it's all about.

And so yes, I have some firsthand experience to share.

And you were like texting me in real time, telling me all about it, and telling me how gross the blue cookie was that you had to eat.

Yeah, the test meal was two big blue cookies that I choked down against my will.

Well, and so maybe can we do a brief overview of Zoe as a company and how they evolved to the point that they're at?

Because I find the history of the company to be really interesting.

Yes, absolutely.

So, all right, Zoe history, as far as I understand, is in 2018, 2019, the Zoe organization, which is based out of the UK, starts this personalized nutrition research project that they do in collaboration with King's College of London, Massachusetts General Hospital, Stanford, Harvard School of Public Health.

So it's this big research effort that they call the PREDICT study.

The aim was to really look at the role of genetics, metabolic differences, the gut microbiome in how we respond to food, our metabolic responses.

So the thing about doing research in 2019 is COVID hits.

And so when COVID hits, the Zoe team did something interesting.

They were like, we have this app that we developed where our study participants are entering real time data about their health.

And so maybe we can use this platform to quickly whip up a COVID symptom tracker.

And so they developed the symptom tracker app that they released eventually to the general population.

And in the first 24 hours, it was downloaded over a million times.

Yeah, that's amazing.

And I would just say, I wanna just highlight how cool it was that Zoe did this to move to an app that was really helpful in tracking COVID symptoms for people.

It's just, what a great thing for a company to do.

Absolutely, absolutely.

Yeah, it was used a lot.

And it was not just in the UK where they're based, it was used all over the place.

And so I'm sure some listeners remember having this app where it was called at times the COVID Symptom Tracker, but you'd see Zoe's name in there.

And it helped gather a ton of data about the spread of COVID.

It helped connect people with tests.

So very cool.

So during this time between 2020 and 2022, they received a lot of government funding that really propped up their research efforts, but also this COVID Symptom Tracker.

But then in March of 2022, the world had changed quite a bit.

The government funding was stopped.

And so this put Zoe in an interesting place because clearly since before COVID, they wanted to create this personalized nutrition product that they wanted to sell direct to consumers.

And now their app was on millions of people's phones and they had massive name recognition.

So they were in an interesting place where they, I think they wanted to capitalize on the fact that we wanted to make a product and now everyone knows us.

And so it's kind of unique.

Yeah.

No, I mean, what a boon for the company.

Yeah, exactly.

So there was this interesting transition period in 2022 where they were like, okay, well, we got to get this product off the ground here.

And pretty quickly they did.

And so they encouraged users of the apps to keep logging their symptoms, how they were feeling, but it kind of shifted slowly from a COVID experience to more of a general health app where you were logging your symptoms about other health outcomes or other symptoms you might be having.

And then it became about the Zoe product that gets shipped to your house that we can talk about.

Well, and yeah, and that's what I want to hear more about.

I want to hear more about the product they're offering, and I want to hear more about your experience actually engaging with the product.

Absolutely.

Do you want to let Dr.

Tim Spector tell us about the program?

Because I do have a clip.

Oh yeah, that guy's everywhere.

We founded Zoe because we discovered that we all had very different biological responses to the same food.

So a one-size-fits-all approach diet just won't work for most people.

And that's why we've created a personalized approach just for you.

Zoe's personalized nutrition program starts with an at-home test of your blood sugar, your blood fat and your gut microbiome.

The insights from that test are provided to you in a comprehensive report, giving you information about your body's responses and advice to eat the right food for your unique biology.

Your results also power your personalized app-based program, providing you access to a library of millions of foods, scored just for you.

At Zoe, nothing's off the table.

This means that instead of removing food from your plate, we teach you how to combine foods so they work for you.

So if you fancy fish and chips, you can have them.

I do fancy fish and chips.

I do, Tim Spector.

I really do.

I do as well.

All I can think about when he talks is how much he sounds like Laszlo from What We Do in the Shadows.

Yes, yes, 150%.

It's like Laszlo offering me fish and chips.

And can you clarify, Matt, what exactly arrives to your door?

What do you get in the Zoe kit when you order this product?

Yeah, good question.

So you get this wonderfully branded yellow box, and inside there's a continuous glucose monitor.

It was a Freestyle Libra, one of the two options.

And you get a kit for doing a blood sample.

You get a bag to send in a poop sample.

You get the test cookies, that there are these blue cookies that we'll talk more about.

Basically, you're testing, you know, the stool sample is pretty self-explanatory.

You're sending in a sample to test your gut microbiome.

The CGM that you wear is to test your blood sugar.

The blood test and the cookies are the sort of the new element here.

So they have you eat this cookie that's a very standardized meal.

They know exactly what's in it.

You have this for breakfast and for lunch.

And then you take a sample of your blood at home at a very specific time point.

And what they're trying to assess here is how much fat is in your bloodstream at that specific point.

Cause they wanna see what you're doing with dietary fat.

How long does that fat stay circulating in your bloodstream and to what degree?

The idea here is what is your metabolic response to fat?

How do you handle it?

And how can we compare that to other people to assess your personal needs?

Does that make sense?

Yeah, absolutely.

And I think this speaks to the fact that one of the things we have learned over the last several decades is that people respond differently when they're eating fat and fat containing meals.

Yeah, and what's novel here is, normally you go to your PCP once a year, you get a blood test and they look at your lipid panel.

That includes triglycerides, which is this blood fat that they're looking at, but they do that test fasting.

So maybe they tell you, I've come in fasting, we'll take your blood.

But this is not a fasting test.

This is what's called a post-prandial test, which means just after eating.

They want to see what you're doing with this food that you took in.

And so this post-prandial test is interesting and it kind of is more catered to the personalized nutrition space than these fasting tests that we're used to.

And I had this experience myself.

And did you love it?

No.

Spoiler alert, I thought it was very interesting.

Kudos to them for a very interesting experience.

But all in all, I did not love the experience of being on the Zoe program.

Well, and why?

What about it?

And also I want to understand where your like clinical mind went as you were analyzing the experience.

Yeah, well, most of my issues lie with the usage of the app, sort of the ongoing experience of being on the Zoe program, getting your meals scored and telling me that my lunch was a 54% out of 100.

That was part of my issue with it.

The other is I think at the end of the day, I didn't feel like there was this magic of personalization where suddenly they saw something in my blood that told them that the perfect food for me is like a chili cheese dog.

It was eating high-fiber foods, being aware of your saturated fat intake, trying to have balanced meals, getting sufficient protein.

The recommendations were exactly what you'd expect.

They were just slightly tuned based on how well you manage your blood sugar and the dietary fat that you take in.

Well, and can we talk a little bit more about how they are scoring meals?

Because that's an aspect of all of these companies that we haven't talked about yet, and that we did touch on very briefly earlier, that typically what these apps are doing is then using an algorithm to recommend food or rate or score the foods that people are eating.

And this is a really, I think, important thing for us to dig into.

Yeah, and so they do cite things like machine learning and kind of this background algorithm that contributes to the scoring system, but they're taking into account your gut microbiome and the type of bugs that you've got in your stool sample that you sent in.

And so we talked about this in our first episode in this series.

We have so much more to learn about how we're gonna interpret the specific bacteria that we find in a stool sample and how that translates to nutrition information.

We are at the very start of that process.

And so I don't have a ton of faith there.

And then you take into account these metabolic responses.

So as part of the Zoe program, I wore a CGM for, I think it was like 11 or 12 days.

And I ate and logged my meals so that they could understand how I was responding in terms of my blood sugar to the food I was taking in.

And then they judge you and tell you, how good are you at managing your blood sugar?

Like what's going on inside of you?

And they do the same with dietary fat.

And then they incorporate that information of how good or bad you are at managing sugar or fat into your scores.

And so they combine various factors and others, like general understanding about nutrition into what ends up being just like a number.

Like, hey, nice job having ice cream and getting a zero for your snack today.

Yeah, and I feel like this is the part that could be really challenging for a subset of people is, we've talked about it in so many ways on the show before, but when there are numbers associated with food, when food is being judged or evaluated, or there's a hierarchy created where some foods are elevated and others are forbidden or supposed to be only consumed once in a while, then you have people who can get incredibly stressed and hyper-focused, and also just feel like they're not doing well with how they're feeding and nourishing their bodies.

Yeah, and Zoe tries to walk the line by trying to get you to, on average, get like a 70% or higher, and they really try to steer you away from worrying about being perfect.

And I will give them kudos for that, but still, is the experience of eating I want to have constantly being graded on my food, or is the experience that I want to have more of like a personal, there's the word, right, a personal experience, or do I want to be interacting with an app that's giving me feedback all the time?

For me, I don't want to be using an app like this.

Well, and also, I mean, so now we're giving a lot of our opinions, but I also want to make sure we dig into the science.

So I also want to make sure that we touch on the science around blood fat response testing, and also just the science generally about whether or not personalized nutrition programs like Zoe, again, for somebody who doesn't have impaired glucose tolerance, show or demonstrate improved health outcomes.

Yeah, no, I think that that's definitely where we should go.

Can I just say, Zoe, if you're listening, those blue cookies are so gross.

Can you change up the recipe a little bit?

They smelled like Play-Doh, and I was like, well, they're not gonna taste like Play-Doh.

They taste like what I imagine Play-Doh tastes like.

And I was like, they give you 20 minutes to eat the cookies.

And I was like, 20 minutes, I can put away two cookies in 30 seconds.

It took me 20 minutes to eat these cookies.

Those things are very hard to eat.

And if the whole point is just to like have a specific macronutrient distribution, you can provide that in other ways than making me eat Play-Doh cookies, please.

Well, and just, you know, for 100% transparency, you were texting me the entire 20 minutes that you were eating the blue cookies being so sad about it.

I know.

We'll put a picture of the cookies on our Instagram if people want to see what that looks like also.

And I will say, the reason that they're blue is because they also want you to log when your poop turns blue in the toilet so they can measure your gut transit time, which I'm not sure how they're factoring that in.

I didn't look too deeply into it, but that was a weird experience to say the least.

Yeah, yeah, I can imagine, I can imagine.

All right, so let's dig into the science.

So this is interesting timing, right?

Because we were recording this, and less than 24 hours ago, the first intervention study was actually published from Zoe, right?

Yes, this was really interesting because up until 24 hours ago, I was definitely going to bring up the fact that, I wish there were more randomized control trials looking at personalized nutrition programs in people without prediabetes and diabetes.

And then Zoe actually published one yesterday, which meant a lot of reading for me last night, but I think is so applicable to this conversation.

Yeah, thank you for publishing this at the perfect time.

Thank you, this is great.

And so, you had a chance to read through this thing.

Tell me, what did we learn?

Yeah, I did.

So this was, they called it the method study, and it was a randomized control trial.

It followed just about 350 individuals, older individuals, 41 to 70 years old.

And it was an 18 week study where they divided this cohort into two groups.

They had a control group, and then their intervention group used the Zoe program.

And what they were primarily interested in is looking at things like triglyceride levels, LDL levels, a bunch of other metrics like glucose and C-reactive protein, which is a marker of inflammation.

In the intervention group, those individuals who followed the Zoe program versus those individuals that were just getting very generalized health and nutrition information from the USDA.

Tell me more about that control group.

What do you mean generalized nutrition information from the USDA?

What did they get?

Yeah, this is really important to point out because the control group essentially was just emailed a USDA dietary guidelines for Americans PDF and a video.

So the control group was sent a video and a PDF and they did have the ability to check in and get one-on-one support if they wanted to.

They were emailed once a week and they were followed up with once a week just to kind of like check in, see how you're doing.

But it was very little support and guidance that the control group got.

You wouldn't love to pour over a PDF of the USDA guidelines.

Doesn't that change your behavior?

Well, like usually, and I mean, I don't know, they didn't have a copy of the exact PDF, but I have seen USDA PDFs that are like 112 pages long.

And so yeah, I mean, that's a lot of information to pour through.

But generally how they described this PDF was that it was giving basic advice about how many servings from each food group to have.

And then they got to watch a video and that was about it.

Okay, all right.

And they're comparing that to the full Zoe experience that other people are getting, where they have an app that they're going into many times a day to log their food, check their score, go through all the educational sections of this app that I didn't mention earlier.

So Zoe is teaching you concepts about nutrition as you go through the process.

And so there's a lot of touch points for the people in the Zoe experience.

The exposure is quite a bit different than the control, which I'm sure they're aware of.

Yeah, yeah, absolutely, absolutely.

So yeah, that was the general study design.

And then I will say that after going through the study, I was definitely underwhelmed by the results.

And so what they found is that there was no significant difference in LDL, blood pressure, insulin, glucose, C-reactive protein, postprandial triglycerides between groups.

I mean, they did find that there was a significant decrease in fasting triglycerides in the group that adhered to the Zoe program versus those that were in the control group.

But as I was reading along, I guess I was just surprised that it didn't really seem to be that different between groups, quite honestly.

Yeah, that is really interesting.

The study period was how long did I miss that?

18 weeks.

18 weeks, okay, gotcha, gotcha.

I mean, a reduction in fasting triglycerides is good, right?

That's cool.

But we are expecting to see like, oh wow, personalized nutrition.

Wow, we're comparing population general nutrition advice to personalizing your nutrition, and we're not seeing that many statistically significant outcomes here.

Sure, and they reported some subjective changes in the Zoe group versus the control group, things like Zoe participants reported improved mood and more energy.

And again, I'm not discounting those things, but those are much more subjective measures.

I just feel like Zoe markets in a way that emphasizes health biomarkers are going to be significantly improved if you use this program.

Yeah, absolutely.

Okay, such interesting timing.

We have the first intervention study here.

I got an email from Zoe yesterday saying, the evidence is in, Zoe works.

And I guess I'm hearing it's a little underwhelming actually.

And so that is very interesting.

I'm so glad we could talk about this.

So maybe we could just kind of open up the floor to discussion here.

Two dietitians ranting about personalized nutrition offerings.

How are you feeling about Zoe now that you've read this study?

So I think the first thing I would want to say is that I want to kind of give Zoe credit where credit is due.

They are much more data and science driven than many of these other companies.

They really do large scale studies, trials, and they're trying to gather more data.

And I think that that's great.

And I also want to just acknowledge that.

I think I would kind of differ in my interpretation of saying Zoe works in a way that makes it seem or sound like everyone is going to really benefit from interacting with this product.

I mean, I think you could learn about your own blood glucose response.

I think you could learn about your blood fat response.

Do I feel like that's going to translate into really specific recommendations that are different than general guidelines, the things that you and I might talk about with folks?

Not really.

I mean, I don't really feel like the RCT that came out yesterday made me feel confident in saying, yes, I really think every person needs to buy this product, engage with it because it's really gonna improve your overall health.

Absolutely, and this narrows the focus of health so specifically, right?

It's like your metabolic response is the only thing of concern.

We absolutely see that with companies like Levels, right?

Who are selling CGMs.

It's like, this is the only thing to think about.

And with Zoe, it broadens what we're thinking about a little to include blood fat and the microbiome, but still it's a pretty narrow focus.

Health is so vast, right?

And I didn't like the experience of getting that boiled down to a score for my food.

And so based on these outcomes in this study, I'm not any more passionate about the use of Zoe.

Well, and the other thing to say too, is that with this study that came out yesterday, the control group, to me, it was very interesting that they chose to just send a PDF and a video to the control group.

Because I would say, and I'm not trying to toot my own horn here, but that's very different than working with a health practitioner on personalized nutrition that way.

I mean, a lot of the work that you and I do, Matt, is very personalized and takes into account chronic disease and health risk and someone's relationship with food.

I mean, quite honestly, many things that an algorithm doesn't take into effect, at this point, at least.

Yeah, not only are the wonderful dietitians out there, like ourselves, but many listening, I would imagine, not only are we taking into account health concerns, we're also listening when you say that your mom made a comment about a specific food when you were 14 years old, and that influences your food decisions now, or you keep trying olives, but you don't like them, but you want to keep trying them, because maybe you'll like them in the future.

Like, there's so many aspects of nutrition care that are so personalized, but that does get lost.

And if I do have a bias here, it's that I feel like there's this idea in the market that nutrition guidance can be mechanized and automated through an app and using the power of AI and machine learning, and it discounts the magic of support, right?

And I think that's a good point to call out that, when Zoe was trying to compare this to a control group, they chose just words on a page or a video you watch, and they discount the lived experience of getting help.

I think where my struggle lies, and I'm guessing yours too, Matt, is the fact that so many of these companies seem to market themselves as having solved the health and nutrition puzzle already.

And again, that's just not supported by the data.

Sometimes I get lost in this daydream about health camp.

Oh yeah, you want health camp for people?

Do you know what health camp is?

Have I told you my daydream?

I mean, no, but I would love you to right now.

Well, I just feel like a lot of these tools, like CGMs or after meal blood fat testing, I think that they shouldn't be done in the privacy of your home without somebody there to really dig into the results with you in a meaningful way.

And I just think it'd be so cool if there was like summer camp where you went and you were given delicious food that we were all aware of the macronutrients in so that we could do short-term use of a CGM, and we could take some blood tests, but also we could go for a nice hike and sing kumbaya around the fire and just have a good time.

And then we'd take that information and you and I and other healthcare providers could be like, oh yeah, look at that.

Your blood glucose control is a little different than other people and your blood fat control is a little different than other people.

We can integrate that into recommendations as healthcare providers.

So you don't have to feel at the individual level like this is just another reason to stare at your phone all day long.

I don't like the implementation of these products.

I think this could be done so much better.

Health camp.

Health camp, baby.

Yeah, can I eat fish and chips with Tim Spector at health camp?

No, no, I'm still thought aloud.

That's not offered at health camp.

All right, so what have we learned in this three-part series?

Can we summarize three hours of content here for everybody?

Yeah, I mean, let's go back and summarize.

What are our main takeaways from these three episodes?

My big one is don't mind the fricking moon.

Leave the moon alone, please.

That's my number one.

Number two, do you have a number two?

Okay, yeah, along those same lines, don't give your DNA to Naveen Jain.

That doesn't feel like a good choice for anybody.

Okay, number three, I'm gonna continue to not take this seriously and say, yeah, at your next cocktail party, tell people you read a cool GWAS and see what they say.

I'm gonna say fourth and perhaps most importantly is that everyone just go live your highest truth, please.

Yeah, 1,000% live your highest truth or if you're not, it's gonna be $500, I'm so sorry.

It costs, we now know that the price of highest truth is $500 with an ongoing subscription.

Absolutely, and then probably also important to say, Tim Spector is Laszlo Cravensworth, long lost brother, we've learned that.

So that's important, I don't know, what else?

I don't know, we just save people $14,000 in products.

So I guess join our Patreon.

Yeah, that's right.

Think about how many thousands of dollars we just saved you.

You don't have to go out and do those things.

You can do other things that will support your health.

I love it's like shameless plug.

Nutrition For Mortals is a production of Oceanside Nutrition, a real life nutrition counseling practice in beautiful Newburyport, Massachusetts, where we provide individual nutrition counseling, both in person and online via telehealth.

Feel free to learn more about our practice at oceansidenutrition.com.

If you want to send in a show idea, you can email us at nutritionformortals.gmail.com.

We're on Instagram at Nutrition For Mortals.

If you're digging the show, tell a friend.

Maybe give us a nice review on Apple Podcasts if you can.

Thanks for listening.

We'll see you next time.

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100 Years of Diet Food

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Personalized Nutrition Part 2: Nutrigenetics (with Dr. Lara Hyde)