Confused about which diet is right for you? High carb, low carb, Atkins, Zone or Ornish? It can get pretty confusing out there! Dr. Christopher Gardner, nutrition researcher at Stanford University and author of the A to Z Weight Loss Trial study breaks down what the research shows on this episode of Dr. Ruscio Radio.
Dr. R’s Fast Facts
- A fascinating discussion with Christopher Gardner, Ph. D.
- We expand on what non-biased studies of high and low carb diets show.
- There is no one diet that works well for all people.
- There are some fundamental dietary principles that are highly beneficial for almost everyone.
- Ruscio recommends starting low carb and then slowly reintroducing carbs to find what intake works best for you.
In This Episode
Fast Facts … 00:04:25
Christopher Gardner intro … 00:06:30
A to Z Weight Loss Trial study discoveries … 00:10:15
Carbohydrate tolerance … 00:15:14
New study details – low carb vs. low fat diet (not published yet) … 00:22:04
Microbiota and genetic mutations … 00:26:54
Inflammation and immune response … 00:35:33
Dietary interventions and common goals that everyone can agree on … 00:38:15
Dogmatism … 00:47:45
Episode wrap-up … 00:49:27
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Welcome to Dr. Ruscio Radio, discussing the cutting edge in health, nutrition, and functional medicine. To make sure you’re up to date on this and other important topics, visit DrRuscio.com and sign up to receive weekly updates. That’s D-R-R-U-S-C-I-O.com.
The following discussion is for educational purposes only and is not intended to diagnose or treat any disease. Please do not apply any of this information without first speaking with your doctor.
Now, let’s head to the show!
Dr. Michael Ruscio: Hey, guys, this is Dr. Ruscio, and before we go into our fast facts, I just wanted to let everyone know that I will be teaching a seminar in London that I’m really, really excited about. It’s a two-day event, January 16 and 17, in London with Melissa Hartwig and myself.
Day one will be a split between Melissa talking about the Whole30 Program and all the great stuff that entails implementing the Whole30 and how to navigate that and just the great program that she’s put together there.
The second half of day one I will come in with what are some first steps someone should go through if they’ve been on a healthy diet like Whole30 and they’re not able to respond fully. This is pretty much what I do in the clinic all day, so I’ll just be expanding upon that.
What I’m really excited about is the second day, which will be an even deeper expansion on all these issues in gut and with a little bit of expansion on thyroid. The second day is geared toward a more educated layperson or a patient who’s suffering with non-responsive problems or, of course, a healthcare professional. We will be offering continuing education credits for that day, and some of the gut stuff should be really, really helpful. Of course, you’ve heard me talk about all sorts of gut “stuff,” to put it loosely, from testing to microbiota to treatments, so I’ll help outline what some of the most common causes of digestive problems are, what testing you can use to figure that out, and that is oftentimes much easier said than done, so knowing how to perform the right tests to get the right diagnosis and also doing it in a cost-effective manner is really what we’re going to be going after.
Another thing that I’m really excited about is a review of all gut and microbiotal interventions. If we’re talking about probiotics or prebiotics or fiber or FMT or fasting or an elemental diet, what kind of effect do those interventions have for things like IBS, IBD, weight loss, thyroid problems, celiac? I will break all of this down so that you will know for what condition you have—or for what conditions your patients have—what treatments are the most viable and the most validated. Then, of course, we’ll wrap that all together with an algorithm, if you will, or putting-it-all-together kind of action steps as to how to sequence this stuff. That will be about 60 percent of day two.
Then the tail section of day two will be on thyroid, something I haven’t talked a lot about lately on the podcast because we’ve been so inundated with gut stuff, but there’s certainly some very important thyroid stuff, as I’m sure many of you have heard me talk about awhile back regarding thyroid diagnosis, types of thyroid problems, and a simplified model of thyroid disorders. We’ll cover sub-clinical hypothyroidism, which is a pretty important issue. We’ll talk about iodine and give you some simple, straightforward treatments to navigate through thyroid.
I’m really, really excited about this. If you’re in the UK, I hope you can make it over to London to check it out. If you see the transcript, you will see the link for this, and if you’re just listening, if you google “Re-FIND Health” and then “Michael Ruscio,” you’ll see my name come up. Hopefully this will be something that some of you can attend, and I think it’ll be very well worth it.
OK, now we’ll jump into the fast facts. Thanks.
DrMR: Hey, everyone. I just wanted to give you your fast facts for today’s call, which was actually a fascinating call with Dr. Christopher Gardner. He is a PhD researcher at Stanford. He published the A TO Z Weight Loss Trial that I have discussed many times and referenced many times, where he took participants and put them on either Atkins, Zone, or the Ornish diet, so comparing essentially a low-carb diet to a high-carb diet, to see what type of effects were elucidated. So we talk about that study and also a new study he has currently running, trying to elaborate on what he found in the initial study, the A TO Z Weight Loss Trial, which was there is no diet that works for everyone, but there are some hints that can help people determine what diet might work best for them. We will go into details in the episode. Sorry for not having a super-detailed fast facts here, but we essentially elaborate on the issue of navigating what type of diet is going to work best for you, looking at the spectrum from low carb to high carb.
I think this will be a very enjoyable episode for people. The principle is actually pretty simple. My take on this is start low carb and then slowly work your way up with time, which actually ironically is the same thing that they’re having their subjects do in the study right now—start with an extreme dietary endpoint. In their new study, they’re having people either start high carb or low carb and then eventually working their way kind of back to the middle to figure out where they fall on the carbohydrate-intake spectrum. It’s a bit simple in practice, but I’m hoping that the episode will give you some good understanding as to the principles and rationale behind why those recommendations are made so that you can then do that in your own life with a little bit more confidence and not get pulled into the latest dietary fad or whatever it is.
So with no further ado, let’s jump in, and I hope you guys will enjoy it. OK, thanks.
Christopher Gardner Intro
DrMR: Hey, folks. Welcome to Dr. Ruscio Radio. I am super excited about today’s guest, Dr. Christopher Gardner, who is a researcher over at Stanford. He published a study that I’ve referenced many, many a time, which is the A TO Z Weight Loss Trial that put patients on different types of diet, Atkins all the way through… I believe it was Pritikin, so you have a low-carb diet all the way through a high-carb diet, and he really did a great job of trying to figure out what type of diet—high-carb or low-carb—works best for what type of person. I really like that approach because that’s very much the approach that I believe in, which is not a one-size-fits-all sort of approach, and let’s just be OK with the fact that there’s going to be some variability. He’s done some fantastic research in that regard, and so I’m very excited to have you here, Christopher. Welcome to the show!
Dr. Christopher Gardner: Thanks, Michael. Pleasure to be here.
DrMR: So can you tell people a little bit about your background and some of what you’ve been doing? Of course, I just alluded to some of that, but a little bit more about kind of what you’re doing?
DrCG: Yeah, absolutely. Actually if you go way back, just for fun, I was a philosophy major undergrad at Colgate University and then a bum for six years, and then I just wanted to have a vegetarian restaurant, and one mistake led to another, and I got a PhD by mistake and a faculty position by mistake, and millions of taxpayer dollars to try to answer nutrition questions.
I really keep just reinventing myself, just following this trail of interesting questions that I originally didn’t intend to answer, one of them in particular being that weight loss study, because when I actually did end up with a PhD and a faculty position, I really was intrigued by phytochemicals and things that weren’t vitamins and minerals. I kept writing grants about soy and garlic and gingko and running studies like that, but when I went to discuss the results, almost without exception people would say, “Yeah, yeah, yeah, so much for that. OK, but I really want to know if I should be on the Atkins or the Zone or the Ornish diet. Which one for weight loss?”
DrCG: And I said, “No! That’s not what I’m even studying!” And they said, “I know, but that’s really what we’re frustrated and confused about,” which led to writing up a grant proposal seven different ways before we ended up with enough money to get 311 women randomly assigned to try to follow the Atkins or the Zone or the Ornish diet, all of which had been, you know, New York Times Bestseller books at one point or another, and we compared all three of those to sort of a health professional’s approach, which was another book that we had from Kelly Brownell called the LEARN manual. That’s how I got into all this.
DrMR: When I first came across your study, across somehow, I stumbled upon a YouTube recording of you discussing the results from the trial, and I had a lot of respect for you right out of the gate when you essentially said something along the lines of: I went into this study as a vegetarian, and then the results are making me rethink my dietary approach. Just the fact that you were open minded enough to be able to have that shift of mentality and to be able to say that publicly really showed me that you’re open minded, and that’s really something I value in health sciences, which unfortunately you don’t always see in health sciences. Sometimes you just see people wanting to reinforce whatever they have previously thought, so I really, really enjoyed the open mindedness, and I want to give you a hat tip on that because that’s just so refreshing to see that.
A TO Z Weight Loss Trial Study Discoveries
DrMR: Can you elaborate a little bit on some of what you found in the A TO Z Trial?
DrCG: Sure, I’d be happy to. At the end of the day, after assigning all these women to these different diets, our main publication, which ended up in a great journal, looked—if you were looking at the graph—as if the Atkins diet did the best, especially after six months. Then on the way from six months to 12 months, there was a little more weight regain in that group than the others. At the end of the day technically, for statistical significance, the only two groups that were different were Atkins and Zone, which is a little odd because those are both the two lowest-carb diets. Neither of those were different than the Ornish, which was super low-fat, high-carb, or the health professional’s diet. So statistically that part was a little odd.
If you go past the weight loss, that being the main outcome, if you look at secondary outcomes, some of those were statistically different among the groups, and pretty consistently all the statistically beneficial findings favored Atkins. Their HDL went up more, their triglyceride went down more, their blood pressure went down more. So partly from a weight perspective, although I have to say those weren’t the strongest findings because they were only different than Zone, and partly from secondary analysis, Atkins didn’t lose. At the time I ran that study, everybody was vilifying that challenger low-carb diet because, of course, for 30 years everybody had been saying low fat, low fat, low fat, so that was just horrific that it could be the opposite.
So that was the main conclusion, but I’d really love to build some enrichment in there, too.
DrMR: Well, one of the things that I really enjoyed from your study was when looking at the Atkins diet—and, please, correct me if I’m wrong on any of these details—but on the Atkins diet, as you said, the total cardiovascular picture seemed to improve in a better direction, and I believe, on the Atkins there was an increase in LDL, which can sometimes really alarm people, but when you looked at that in the context of looking at their HDL, which went up, as you said, and I believe blood sugar levels or triglycerides and blood pressure, although maybe not significantly improved, but all these other markers seemed to improve, so while, yes, the LDL did go up a little bit in the Atkins group, all these other cardiovascular markers improved, giving you a net effect of being favorable. Am I restating that accurately?
DrCG: Yeah, that is pretty accurate—as a group. The important place I want to get to is the massive individual variability plus, before I even go there, let me tell you one interesting thing that I’ve had to do. I made some people mad who were the authors of these books when their book didn’t win, but we also did a lot of diet assessment. We got—I can’t remember—something like 3000 days of dietary records from the different participants, and if you follow those data in the paper, you can see that the participants, on average, were not eating the diets as described in the books. So I always have to be really careful and say this is what happened in the group assigned to Atkins and assigned to Ornish because they really weren’t. I even had one convoluted argument from the Barry Sears group saying that, you know, if you look at the folks who were assigned to Atkins, by the time they finished the study, they were closer to the Zone 40-30-30 than any other group, so really the Zone diet is the best, to which I have to say, so wait a sec, let me scratch my head here. You might have had the best result with the Zone diet, but to eat the Zone diet, you have to try to eat the Atkins diet. Argh!
DrMR: That’s what I really liked about the way you laid this out, though, is it was very practical, it was very real world. If we tell someone to do the Atkins diet and we give them some coaching on the Atkins diet and we give them the book, they’re going to eat this way, not exactly the Atkins, but close to it or a little different, but they’re going to end up with this outcome. As a clinician, I really liked that because that’s what I’m going to do in the office. I’m going to give maybe someone the book or some literature and give them a little bit of coaching, and then they’re going to go out in the world and do what they are going to do, and it’s very helpful for me to know that if we were to say “Atkins,” it may be a little bit closer to the Zone, but they’re aiming for the Atkins and maybe falling a little bit short, I guess you could say, of the carb restriction.
DrCG: Yeah, and if the data supported what was really going on. If you asked them to follow the Zone and they didn’t, you wouldn’t get the results you wanted.
DrMR: Exactly. Yeah. That’s actually a really interesting point.
DrMR: Now, there’s, of course, this, I believe you termed it “heterogeneity of insulin sensitivity,” or as I always say a more simple way of maybe saying that is that people have a different ability to tolerate carbohydrate, and this was one of the most fascinating pieces of your study. Again, I’ll try to recapitulate this or reiterate this—and, please, expand—but you essentially noticed that some people seemed to improve via various health markers on any diet, whether it was a higher-carb or a lower-carb, and the people that seemed to be able to improve—I guess let me take a step back. The thing I really like about that is if someone were to recommend a lower-carb diet, there’s always the counterpoint to that. “Well I have a friend that went on a higher-carb diet, and she lost weight and she feels great.” I think we should always be open to those things because if they exist, they exist for a reason, and so the reason why I love the fact that you really dug into the details is because it accounts for this.
Essentially with the examination of the insulin sensitivity, it seems like people that are very insulin sensitive, meaning they process carbohydrate very well, they seem to be able to improve their health on any kind of diet, any kind of healthy diet as the ones you laid out in your study, but it’s the people that have more of a predilection toward insulin resistance, pre-diabetes, diabetes, or that just have a harder time processing carbs that tend to do better on the lower-carb diet. That was one of the most ingenious findings.
I’m sure you have a lot to say on that, but where would you expand on that idea?
DrCG: Sure. Well, part of the way I want to expand it is a big 600-person study that we have underway that’s looking exactly at that, but let me back up and tell you kind of how I got there, which was fun.
I had a postdoc at the time who said, “I know that we had a lot of variability in adherence to these diets, so I wonder if we just broke it out by who adhered to the diet and who didn’t and we came up with these different metrics for adherence for the three popular diets”—it was actually pretty hard to come up with one for the health professional’s diet, for reasons that I don’t want to go into here, but she published a whole paper on just that, and we took sort of thirds of people within each group, the third that was the most adherent, the middle, and the least adherent, and we looked at their weight loss. And really, on all three popular diets—Atkins, Zone, and Ornish—it was pretty much the same, the same amount of weight loss and quite a bit. And then you looked at the third that was the least adherent and they pretty much had no weight loss in all three groups.
That really doesn’t sound like rocket science that will make anybody fall off their chair, but at the time, I thought, “Let me look at some insulin resistance findings, too.” We had a very crude proxy for that. We only had fasting insulin, and we broke them into tertiles, and we were looking for differences in weight loss that way. I’d seen a couple of very small metabolic ward studies that had shown exactly what you described just a few minutes ago, and we saw the same thing, particularly in the group that got assigned to try to follow Ornish. When they tried, actually they didn’t do very well. On average, they ended up following the national guidelines, the 30-percent fat diet when, in fact, the Ornish program is 10%, so they fell far short of that objective, but among the group that got assigned to Ornish, the least weight loss was the ones who got assigned to that diet and had the highest fasting insulin at baseline, so just what you said. They’re having a harder time putting away carbs. They get assigned to the low-fat, higher-carb diet, and they don’t lose weight.
Well, that finding came out just at the time as the adherence paper came out from the other postdoc, and I said, “Well, to do due diligence, I should actually look at this.” Nobody knew what their insulin results were, so nobody would have known by our criteria whether they were more or less insulin resistant. And they all had the same fabulous teacher. I can’t imagine there was any difference in adherence, given that they didn’t know what metabolic state they had. Well, I looked, and in fact, the ones who were more insulin resistant by this crude measure were significantly differently and less adherent than the others. That spoke to me, saying maybe there’s something physiological here. So you assign them to this diet, and the person next to them in the classroom, the weight is coming off and theirs isn’t, and they’re growling and grimacing and frustrated and beating themselves up. “Maybe I’m just a sloth. Maybe I’m just a worthless person. I can’t do what this person next to me is doing.” But what if there really is a metabolic predisposition that says those folks, as much as they try to be like their neighbor, can’t because they are insulin resistant. They’re predisposed to having a tough time putting carbs away, and we just put them on a low-fat, high-carb diet. Couldn’t adhere, couldn’t lose as much or any weight.
That led to creating a whole new grant application, which I’ll tell you about in a sec, but I’ll pause to give you a chance to respond yourself.
DrMR: Yeah, one of the things I’d be curious to get your take on is how we take that and then how do we apply that in terms of guiding people through dietary recommendations? One of the things that I like to do is start people initially on a lower-carb diet. Usually I have people shoot for 100 grams a day or a little less. I’m not overly particular. I just want to get them on a lower-carb diet for a little while. And over time, we’ll then have them slowly increase their carbohydrates. Usually what I’m looking at initially—I see a lot of patients with different gastrointestinal disorders, and oftentimes a lower-carb diet can be helpful, especially initially, for this population. So if people come in with different gastrointestinal problems or if they already have a bit of insulin resistance, visiting low carb for a little while and then once the patient is improving and they’re kind of stable in that improvement, we start to have them slowly titrate up their carbs to try to figure out what level of carbohydrate intake works best for them. That’s the way I’m trying to navigate through this. What are your thoughts on that?
New Study Details – Low-Carb vs. Low-Fat Diet (Not Yet Published)
DrCG: Ah! What a perfect segue! Nobody out there listening to this is going to believe that we haven’t talked before! Let me tell you what we did in this new study. OK, it’s related to the old study—
DrMR: Chris, sorry. I don’t want to interrupt you, but I just want to make a note that this study is not published yet, because I know people will probably be asking for the link. This is a non-published study, right?
DrCG: Ongoing and not finished, so really I’m just going to be talking about mostly some design aspects.
DrCG: OK. To go back to the old study just for a moment, one thing that I didn’t state clearly was that in all four of the diet groups from the A TO Study, which was published back in 2005, some of the women lost 25 kilos, so 50-plus pounds, and some of them gained 5 to 10 kilos, so there was a 50-to-60-pound range of weight loss change in all four groups, which was way different than the average difference among all four groups, which was just 3, 4, or 5 pounds. It was trivial.
DrCG: I mean, it might have even been statistically significant for Atkins and Zone, but you wouldn’t want to spend 12 months on one diet versus another if you had 15 to 100 pounds to lose and you really only wanted a 3- or 4-pound difference. You’d want a bigger difference after putting all that effort in. So as you mentioned before, I was fascinated by this huge heterogeneity, this variability when they got assigned to the same diet.
One of the things we noticed in the old study was that the Zone and the LEARN manual diets were more middle of the road, and at the end of 12 months, those had kind of blurred together. They were almost indistinguishable. The two that remained distinguishable were those assigned to Atkins and assigned to Ornish. They didn’t actually follow Atkins, and they didn’t actually follow Ornish, but when they fell short, those had been so extreme to begin with among our four, they were still quite different at 12 months.
With this in mind, we wrote a new grant, and we said all we want is a low-carb versus a low-fat diet. And as much as the NIH reviewers are going to hate this, we are not going to pick a level of low fat or low carb. We’re going to approach it this way: We’re going to ask them to sign up for 12 months, get randomly assigned to one or another, and let’s put your numbers in perspective. Your 100 grams of carbohydrate would be 400 calories. In a 2000-calorie diet, that would be 20 percent of calories from carbs. Yeah?
DrCG: So we signed up and told them ahead of time that once they get randomized, their objective in the first eight weeks is to get either to 20 grams of carb or 20 grams of fat, depending on their assignment. And we didn’t even care if they got there or not. It was to attempt to get there. Now, I will tell you that all 609 people are the past the eight-week mark so far. According to our data, about 95 percent of them got to 20 grams of carb or 20 grams of fat.
Now, we opened up saying, “This is not where we want you to end up being in the end. We want you to have a diet where you’re not hungry, you’re not feeling deprived, and you could look us in the eye and say you could do this for the rest of your life, and nutritionally speaking, I would be uncomfortable if any of you stayed at 20 grams of carb or fat for the rest of your life. You’d be missing some important nutrients, but we want to anchor you at these lower levels, and then”—I’m going to just steal your words because we used them with all these people—”we want you titrate up. So start at 20 and then add five and then add another five the next week. And if you’re still losing weight and doing OK, add five more, but if the weight starts coming back on, either stop adding or even go back down a level, and titrate to the point where at six months or so you feel like, again, you’re not deprived, you are satiated, you’re enjoying your food, it works socially and all kinds of other ways, and you can look us in the eye and say you could eat this way for the rest of your life. You are going to help us define what a realistic low-fat/low-carb is, but we want it to be as low as humanly possible for the sake of the study.”
So we are completely aligned with your thinking, Michael.
DrMR: That’s awesome. I like to think I’ve been giving patients sound information for the past couple of years! Gosh, I am so excited to see the results of this study when they’re finally published.
Microbiota and Genetic Mutations
DrMR: One of the things that this might be a nice transition point to is you were looking at microbiota in some of these individuals and also certain gene polymorphisms, or SNPs, and so I’d love to hear—if you’re able to talk about it—if you’re seeing anything there that may be a predictor of if someone will do better or worse on a high- or low-carb diet.
DrCG: Well, you’ll be disappointed because we haven’t broken the blind, so we don’t really know how anybody’s doing, but I will build on that. We did a pilot study to prepare for this, and in the pilot study, we don’t have any microbiome data at all, and we don’t have any genetic data either, but we still did see this massive variability in one group versus another, and we were looking at how they were doing this, so let me add one more component to our approach.
This is not very sexy, and we have to find a better name for this, but we call it the “limbo-titrate-quality method.” The limbo was get down to 20 grams of fat or carb. The titrate was to work your way back up to a place that’s comfortable. The quality was hugely important to us. We told everybody in both groups: No added sugar. Try to cut back as much as humanly possible. No white flour, not even any whole wheat flour. If you’re going to have any grains at all, and that’s mostly just the low-fat group, they need to be wheat berries and quinoa and amaranth and really seriously whole grains. So we were really interested in quality, and when it’s fats, we want quality fats, and we don’t want you to be having packaged, processed food that says ‘low-fat’ or ‘low-carb’ on the label. Packaged, processed food is crap. So go to the farmers’ market and everybody should have a salad every day, as many vegetables as humanly possible. And the low-fat folks, they get to put balsamic vinegar and lemon on it and lots of tasty, crunchy veggies. The low-carb folks get to be avocado on it, nuts and seeds and oil. The whole goal there was to not set up a straw man to knock over, to not have one of the two diets be really good and the other one technically meeting the criteria but really not being a very good quality diet.
So let me tell you what happens when you do this. You get this massive range of people understanding the “quality” part. Some people really get it, and some people really only focus on the numbers. But if you do separate them out into how much fiber they’re getting, fiber being our favorite prebiotic, wanting a diverse set of types of fiber to feed the resident bacteria in our GI tract, quite clearly the low-fat folks are getting more carbs and more fiber, and the low-carb folks are getting way less added sugar, they’re doing even better at that, but their fiber is going down. So if we’re talking about feeding the resident bacteria with diverse fiber, we don’t have any data on it yet, but the low-fat folks because of their higher carb intake and more grains and more beans are going to be getting more and diverse fiber.
So I’m going to throw it back to you as a clinician. Given how little we know about the microbiota, but how exciting it is, let’s say on a low-carb diet you lower their triglyceride, lower their blood pressure, raise their HDL, their LDL went up a little but not all that much, and somehow you limited the diversity of their microbiota. What would be the net benefit there that you would tell that next patient that comes in? Do we know enough yet to say, “Oh, your lipid profile improved, but because you had less fiber in your diet, your microbial diversity also decreased at the same time.” What if I throw that back to you?
DrMR: Well, you ask a great question, and I love the fact that you’re focusing on quality and not, as you said, trying to set up a straw man for one diet masquerading like a high-carb diet but actually being an unhealthy version. I like the fact that you’re trying to be very true to this and very scientific and nonbiased, I guess. That, I think, is phenomenal.
Then coming back to your question, which is a fantastic question about the microbiota and the diversity, I like to look at this through a very practical lens, which is looking at the net picture of the patient, and usually what I find is we’re either moving in the right direction or the wrong direction. If we’re moving in the wrong direction, we have to modify what we’re doing. If we’re moving in the right direction, we’ll keep doing what we’re doing. I know that sounds a little bit primitive, but let me expand on that a little bit.
Usually when someone has better energy and better sleep, that usually correlates with their digestion also being better and some of their lab values, like C-reactive protein or their HDL and LDL, looking better. I try not to look at any one marker and make a decision based upon that, but I try to look at, OK, we have eight things we’re monitoring here—maybe a few lab markers, maybe several subjective issues like sleep or weight—and so I look at, are we overall moving in a good direction or a bad direction? That’s usually my ultimate clinical determinant, but I should mention with the microbiota—and this is something that I’ve looked into quite thoroughly—there’s so much that we don’t know that I really recommend caution with steering health decisions based upon microbiota findings, and there are a couple of reasons for this.
One, there have been some conditions, like celiac, hypothyroid, and hyperthyroid, for example, that have been shown to have increased diversity. So the diversity piece I think we don’t have completely ironed out yet. Even though there does seem to be this trend where healthier populations have higher diversity, there’s also another interesting piece in here, which is sometimes we’re comparing ourselves to other populations and another population’s microbiota may not be healthy for us. I think Sub-Saharan Africa having a high level of methanogen archaea in their gut, when we have a high level of those in Westerners, that causes quite a bit of constipation and has even been correlated with weight gain.
A couple of thoughts on the microbiota there, and then one final one is that we don’t get a window into the small intestine, which is responsible for 90 percent of caloric absorption and over 55 percent of the entire gastrointestinal tract and the largest density of immune cells in the gut. The microbiota stool testing is incredibly interesting and something that we need to learn a lot more about, but just looking at a diversity score doesn’t mean a lot to me right now because there’s just so much that we’re not seeing with that.
And then maybe one final thing here while I’m on a good rant! When we look at clinical interventions for things like IBS or things like IBD, a lot of times a lower-fiber diet can help with those conditions initially—not forever—but initially it’s certainly been shown that with different forms of inflammatory bowel disease and with different presentations of IBS, a lower-fiber diet in the short term can help re-balance the ecosystem, so to speak. So it’s kind of in alignment, I think, with this picture that we’re painting, Christopher, or at least part of the picture, which could be to start lower carb and then a little bit later down the road start to slowly titrate your carbs upward to see where you feel the best. I think what this will do is it’ll help people balance out, “OK, my gut is very prone to small intestinal bacterial overgrowth, so I may not be able to eat a copious amount of fiber, but I do need some carbs, and so I’m going to slowly increase my carbs until I find that fine point where I’m getting enough carbs and fiber but I’m not getting too much.” That’s where I think the approach of starting low and titrating upward can work really well for people.
Hopefully some of that made a little bit of sense!
DrCG: Once again, we’re totally aligned.
Inflammation and Immune Response
DrCG: The segue here to start with is immune function. One of the advantages I have on this fabulous campus is we have a world-class human immune monitoring core, the idea being that the gut bacteria in the large intestine probably generates short-chain fatty acids, which get absorbed, and there’s probably some leaky gut syndrome going on down there, and that really the clinical manifestation of all this does have to do with immune response. So I’m now working with the folks from the human immune monitoring core to take blood samples, and they’ll be looking at a battery of 63 different cytokines, which, to be honest, kind of boggles my mind. I think that’s probably—
DrMR: Yeah, that’s a lot.
DrCG: —a lot, but that’s the standard assay that they’re doing right now, so another piece of this puzzle to add in is if you can see some of these markers of inflammation, which is yet another field that is not clear cut yet. Clearly inflammation and underlying metabolic dysfunction along the lines of inflammation is fascinating and important, but we don’t have cutoffs like we for HDL or LDL or triglycerides. We just have all kinds of cytokines and other inflammatory markers floating around. But to add to the puzzle, we will be doing the microbiota and the inflammatory markers and the LDL particle size and different lipoprotein particle sizes and trying to add all those together to get a richer picture because we are once again—without breaking any blind—we’re once again getting people who lose 60 pounds and people who lose zero.
DrCG: And everything in the middle. So our goal in this study is actually not to show that low carb or low fat is better. Our whole hypothesis is that some people are predisposed to do better on one than the other and there’s probably some kind of genetic/metabolic/microbiotic fingerprint that would help us understand that, and that might sound fascinating and like great precision medicine, but let me pull it back to your clinical population and see if this part resonates with you. Having said all that—and I’m really having more fun than it’s even fair to have, but I’m working with some phenomenal colleagues, and we have a great study with more data—I mean, this is going to be the study that lives and gives forever and ever because there are so many angles to take on this—at the end of the day, what should folks eat? Should they be more confused? Should they be waiting for this?
Dietary Interventions and Common Goals That Everyone Can Agree On
DrCG: I’m going to spin it in a slightly different way because I had the opportunity to moderate a debate at the Institute of Functional Medicine for the paleo diet, the vegan diet, and the Mediterranean diet.
DrMR: That must have been interesting!
DrCG: It was so fun.
DrMR: Is that on tape somewhere? I’m sure people would love to view that. Do you know?
DrCG: We tried that and it didn’t work, so at the moment it’s not available. It may be someday, but I can summarize it for you.
DrMR: Yeah, please.
DrCG: Here’s the take-home message you get from this. I think you’re going to like this. They all stood up and overly simplistically said, “My diet’s better, and here are the data to prove it.” So I said, “I’m a scientist. You all cherry-picked your data. If you give me a few minutes, I can come up with data that refute yours. We shouldn’t sit here and quibble. Let’s see what we can agree on. So let me ask if anybody here is in favor of added sugar. Let me see if anybody here is in favor of refined flour, even whole wheat flour because it’s heavily processed wheat.” Nobody was in favor, not across all three groups. I said, “How much of the American diet, do you think, has added sugar or refined flour in it?” and they said 70 percent. I said, “Holy crap! All three of you want Americans to change 70 percent of their diet! OK, so what do you guys agree they should add? You guys all agree they should add vegetables, totally in agreement. Do you guys all think they should add fruits?” No so much in agreement, and then it started going downhill from there, so I said, “You want Americans to get rid of 70 percent of what they’re eating and then add vegetables back, so how many vegetables do you think it’s humanly possible to eat? Can you eat 70 percent of your calories from vegetables?” Oh, no, no, no. Maybe 20, 30, or 40. So I got them to agree on that—get rid of added sugar and get rid of refined flour. There you go. There’s your approach right there, Michael, of having them cut way back on carbs immediately. That would be instantly 100 grams of carbs if you got rid of most of that.
DrCG: And then what should they eat instead? Well, the paleo guy said, “You should be having eggs for breakfast and grass-fed beef.” And the vegan guy said, “No, no. No eggs and butter and sausage. You should be having whole grain and beans.” And the Mediterranean person said olive oil and lentils and these things.
So it was pretty fun to see that they actually agreed on some major components to get out of our diet, which are entirely consistent with lower carb. Add as many vegetables back, so don’t be afraid of carbs in vegetables. Eat as many as you can. And I think what we’re left with at the end of the day is what our study is going to show. We’re asking all the low-carb folks to get rid of added sugar, refined flour, and eat many vegetables a day, and have eggs for breakfast and grass-fed meats and organic avocados, and then we’re asking the low-fat folks to get rid of the same thing and include all those vegetables and have all those salads and have wheat berry salad and quinoa and legumes and beans and refried beans and pinto beans, and we’re seeing people succeed and fail on both of those, too.
DrMR: Yeah. I think you make such a great point, and this is a point or a principle that I’ve really tried to hammer home and reiterate with my audience, which is there are important dietary principles that we want to adhere to, and they’re not super technical. I know sometimes people want to make the latest and greatest and sexiest and most detailed and most elaborate-sounding dietary recommendation, but in my clinical experience, usually we have a vicinity we want to get someone with the diet, and then if they’re still not feeling well, there’s usually something else that’s causing the problem. It’s a non-dietary problem. It may be a lack of exercise, a lack of sleep. It may be a lack of socialization. It may be what I see a lot of, which is different gut disorders, like somewhat active inflammatory bowel disease or small intestinal bacterial overgrowth or a fungal overgrowth or what have you.
I think it’s really important for people to hear repeatedly that just as you said, Christopher, there are these general dietary principles that we want to adhere to: Get rid of processed food. Get rid of added sugar. Eat lots of vegetables. That’s a hugely important principle. And then the rest you may fall into a more vegetarian, higher-carb sort of approach, but as long as you’re doing it within those confines of it being healthy foods, some people are going to do great on that. And at the other end of the spectrum, you may add in more of a paleo, rich, healthy fats and proteins, and some people will do great on that, but I think the first step is to get rid of all the garbage stuff in the diet that no one agrees we should be eating, and then the next thing is there’s this spectrum where at the lower-carb end you might be a little more paleo like and on the higher-carb end you might be a little bit more Mediterranean or vegetarian like. And you should go through the process of trying to figure out what spot on the spectrum you feel best at. And then if you’re still not happy with how you’re feeling or there’s still a health condition present, I really think it’s a good idea to look into what else might be happening internally to cause the problem because a lot of the patients that I see get so neurotic with their diets that they should have their nutrition PhD by the time they come to see me as a patient because they’ve just gotten so zoomed in on it, and it almost becomes, I think, counterproductive to health at that point.
But I think you’ve laid out a very nice scenario here where there are some general dietary principles that we want to adhere to, and as scientific as we try to be, sometimes these things are really practical or practically discerned, which is do some experimentation and see if you can nestle in on the spot of the macronutrient consumption spectrum where you feel best.
DrCG: Yeah, and one takeoff on that might be this: What if you do have somebody who’s insulin resistant at the moment and you put them on a lower-carb diet and they lose a lot of weight and they actually become more insulin sensitive? My next follow-up question I have for another day is, does that then open up a broader range of food choices that would be OK for them? Whereas I probably really would have suggested lower carb to begin with, does that recommendation loosen up a little bit as their metabolism changes? I can’t change their single-nucleotide polymorphisms, I could probably change their epigenetics, but what if I have really changed their glucose and insulin dynamics so that they really have a healthier homeostasis mechanism going on? Maybe they need that jump start and then later they can open themselves up to more of those foods that they were missing, but you said this already in the talk, that sometimes you need this jump start.
DrMR: Exactly. Yeah, I totally agree with you, and I think the healthier we get, the broader our diet can be, and ultimately we should be trying to move toward the broadest diet possible, not the most restrictive diet possible.
DrCG: And have it be fun. I just came back from another consensus-building type of thing in Boston last week, Michael. It was the Oldways Preservation Trust 25th anniversary. This is the group that when the original food pyramid came out 25 years ago or 1990 or whatever that was, they created the vegetarian pyramid, the Latin American pyramid, the Mediterranean pyramid, these alternate pyramids that were based on common sense and culture and heritage that have been going on for thousands of years. For their 25th anniversary, they pulled together 25 scientists and 25 members of the press and asked them to find common ground. They invited paleo people and vegan people, plant pushers and animal pushers, zealots, etc. We all sat around the table, and the whole goal was to find the common ground, and they really did agree on a lot, and they agreed on some simple things like, you know, whatever new study comes out today never overturns everything that happened in the last 50 years. You add that, and then you see what the new data adds to the existing body, and it’s never as crazy as the headlines say.
A lot of it is like you were also just saying, that after you get those basics down, you experiment with yourself and you find out which way works for you, but of the 11 sort of common-ground principles we came up with, I have to tell you one of my favorites. I think you should be able to find this online somewhere under Oldways Preservation Trust. This was a meeting in Boston that just happened two weeks ago. “Your food should be good for you, good for the planet, and it should taste good.” And after “good” it says “unapologetically delicious.” We really should enjoy our food and not freak out so much about it unless… yeah, I mean, there are some occasions when you really have to be strict, but if we just enjoyed our food more and got a little less hung up about some of the specifics, our lives would probably be a lot better.
DrMR: Christopher, I agree and I’m just so happy to hear you say that because one of the things that I’ve commented on is something along the lines of dogmatism can only exist in the presence of ignorance. I’ve cautioned my listeners that when you come across someone who has a very strong, hard-headed view on something, to be careful because in my experience, usually when someone has a really hard agenda like that, they’re not looking, as you said, at all the evidence and trying to see what the trends are or what we can all agree on or what a reasonable conclusion is. Rather, as you also mentioned before, they have a position—let’s say they’re paleo—and they’re cherry-picking data to reinforce the paleo position rather than looking at the science to help update their opinion. You, being such a credentialed researcher, in your own way, I think, saying that same thing, that let’s be careful about a really extremist approach and focus on the fun in food and focus on some of these major principles, I think that’s brilliant. Thank you, because I think there are a lot of people that really need to hear that.
DrCG: Great. And when they go out with their friends and see the one person is thriving on a diet, they shouldn’t just follow them blindly. It might be that something else works for them, and that’s fine, too, but they should enjoy food, and they should sit down and eat together and cook together and know where their food’s coming from.
DrMR: I agree. I think that’s a great message to bring us home.
DrMR: Christopher, is there anything you want to make people aware of, or where can people find you if they want to read more or hear more from you?
DrCG: Oh, I’m a horrible social media person. I don’t Twitter, I don’t tweet, I don’t have any Facebook—I don’t have anything. We do have a Nutrition.Stanford.edu website where you can see the different kinds of studies that we run. I have a bunch of podcast-type things. If you just google “Christopher Gardner at Stanford,” you’ll find a bunch of things. That’s a pretty easy thing to do these days.
I’m happy to share any of the results we have. I’m looking forward to finding more practical solutions and practical advice that merge evidence with some of the practical stuff that folks really like to know, and in that regard, I want to throw it back to you and thank you for being the clinician that you are and as open minded as you are because that’s what we need, is we need some of this science translated to the people who really need the advice. We scientists sometimes really suck at doing that because we get caught up in getting that headline and getting that big paper out, not really appreciating that we’ve just confused people more than help them, so, Michael, thank you for all that you’re doing.
DrMR: Thank you, Christopher. This has been such a great call, and I hope you’ll come back on when you publish this study and expand on it.
DrCG: OK, that would be fun.
DrMR: Awesome. Well, Chris, thanks again. It’s been a great call. Have a great holiday, and thanks again for coming on.
DrCG: Thanks to you and your listeners. Bye, Michael.
DrMR: Bye bye.
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