Artificial Sweeteners and Your Microbiota with Dr. Susan E. Swithers – Episode 38

Dr. Ruscio interviews Susan Swithers, Ph.D., Director of Undergraduate Studies Department of Psychological Sciences College of Health and Human Sciences at Purdue University in this episode of the podcast. Dr. Swithers’ lab studies the effects of experience on the development of controls of ingestive behavior and body weight, recently focusing on artificial sweeteners.

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Dr. R’s Fast Facts

  • Most data show no positive impact from artificial sweeteners (AS).
  • Some observational data shows AS may cause harm; altered satiety, weight gain, fat gain, increased blood sugar/diabetes, cardiovascular disease and hypertension.
  • Because AS do not show clear benefit and there is evidence showing they may cause harm – one should only use AS occasionally.
  • Artificial sweeteners and sweeteners in general should not be used every day.
  • AS may cause fat gain around the abdomen.
  • AS may have a negative impact on your microbiota Trusted SourcePubMedGo to source.
  • People with certain microbiota types; know as AS responders, may be at increased risk for a negative reaction to AS Trusted SourcePubMedGo to source.
  • Stevia – just because it is natural does not mean it is safe. We do not have adequate long-term studies showing Stevia is safe or beneficial. Because of this it is best used in moderation.
  • You can reduce your sweetener intake by slowly decreasing your use. Over time, as your body adjusts, you should need less sweeteners.
  • For more on this, my upcoming eBook on the microbiota has a great section on artificial sweetener’s impact on your gut and your microbiota.

podcast-artwork new

Fast Facts…..0:57
Dr. Susan Swithers Ph.D into…..3:21
Artificial Sweeteners – satiety and glucose metabolism…..5:11
Artificial Sweeteners – weight gain and health…..12:32
Interventional studies on the artificial sweeteners…..18:31
Dr. Swithers’ opinion on the health of artificial sweeteners…..24:05
Artificial sweeteners and the microbiota…..26:50
Beverage industry advertising tactics…..41:42
Dr. Swithers’ most recent worst health choice…..44:15


  1. (5:01) Dr. Swithers’ study Trusted SourcePubMedGo to source
  2. (18:17) San Antonio Longitudinal Weight Loss study Trusted SourcePubMedGo to source
  3. (26:50) Suez paper on AS and microbiota Trusted SourcePubMedGo to source

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Artificial Sweeteners and Your Microbiota with Dr. Susan E. Swithers

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 and sign up to receive weekly updates. That’s

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!

Fast facts

Dr. Michael Ruscio: Hey, guys. Great episode today with Dr. Susie Swithers, who is a researcher at Purdue, on artificial sweeteners, their effect on your health, and their effect on your microbiota. I just want to give you the fast facts.

Most data show no positive impact from artificial sweeteners. Some observational studies show that artificial sweeteners may actually cause harm—alter satiety, weight gain, fat gain, increased blood sugar levels and/or diabetes, cardiovascular disease, and hypertension.

So because artificial sweeteners do not show any clear benefit and there is evidence showing that they may cause harm, one should only use artificial sweeteners occasionally. Now, this also includes regular sweeteners. Of course, one should also only use regular sweeteners occasionally, not be using them constantly.

Additionally, artificial sweeteners may cause fat gain around the abdomen specifically. Some data has shown that artificial sweeteners may have a negative impact directly on your microbiota, and people with certain microbiota types known as artificial sweetener responders may be at increased risk for negative reactions to artificial sweeteners.

Stevia—just because it’s natural does not mean it’s safe. We do have adequate long-term studies showing stevia is safe or beneficial. Because of this, it is best used in moderation.

Ideally what you should try to do is gradually reduce your sweetener intake over time. This will allow your body to adjust and ideally not require as much of a sweet stimulus to have the response of being satisfied that you may need. I share an example of how I did this with coffee in the podcast, but essentially just gradually taper down your use, and you should see your body adjust, and hopefully you will require less sweetener over time.

And a final point here: This is maybe one of the favorite sections of the eBook on the microbiota that I’ve been working on. I think you guys will really, really enjoy this. It came together really nicely. That will be out, hopefully, within the next couple of months. I’m working diligently on that, so stay tuned, and with that, we will jump into the show.

Dr. Susan Swithers, Ph.D., intro

DrMR: Hey, folks. Welcome to Dr. Ruscio Radio. I am with here with Dr. Susie Swithers, who is a Ph.D. at Purdue, and she wrote what I think was one of the best papers I’ve read lately on the impact of artificial sweeteners on our overall health and some of the ties into the microbiota, so I shot her an email, and she was gracious enough to take a minute to speak with us. So Susie, thank you so much for being on the show. Welcome!

Dr. Susan Swithers: Thanks for having me!

DrMR: Can you give people a little bit of insight about what you do over at Purdue?

DrSS: Sure. My research for the past 10 years or so has really been looking at the question of whether artificial sweeteners, high-intensity sweeteners, these sweeteners that provide a very sweet taste without calories, looking at whether those can deliver on the promises that people think that they’re going to get from them. Most people turn to artificial sweeteners because they’re concerned about their health, and they think that they’re going to help them be healthier and have better lives, and we’ve really been interested in trying to figure out whether or not that’s true.

DrMR: Right, and I could tell from reading your paper that you’ve really been following this issue quite closely because you provide a really nice, detailed overview of the evidence that we have. I love the way that you just weighed the evidence, and it didn’t seem like you really had a bias, and you were just really trying to get to the truth of the matter.

There’s a number of things I’d love to get your expansion on. I know that in the paper (1a Trusted SourcePubMedGo to source) you discuss the hypothesis that artificial sweeteners may interfere with satiation and glucose homeostasis, so might you be able to speak a little bit about that?

Artificial sweeteners – satiety and glucose metabolism

DrSS: Sure. In a lot of our work, one of the things that’s really hard to do when we’re asking questions about things like artificial sweeteners is to ask these questions in a very straightforward way with people because their diets and their habits are so complicated, so we use an animal model to ask our questions because it allows us a lot more control, and it gives us a way to look for what we like to call “biologically plausible hypotheses.”

DrMR: Mm-hmm.

DrSS: People generally have been led to believe, it just seems to make common sense that an artificial sweetener would be a good thing, and they’re often recommended for people who have particular concerns about regulating their blood sugar levels, with the idea being that when you consume one of these, there’s no actual sugar going into your body, so it should be a good thing.

DrMR: Right.

DrSS: I come from a background where my training is in psychology and in learning, and I’m really interested in how experience with food can affect our future response to food. And so from a learning perspective, the idea really is that that sweet taste really ought to be a very good predictor for our bodies that sugar and energy is going to show up. In the real world where there are no manufactured sugar substitutes, anything that tastes sweet, when we get something sweet in our mouth, our body is going to get sugar. And in order to deal with that effectively, we have to mobilize a bunch of physiological responses. We release hormones to help us metabolize the sugar to keep our blood sugar levels where they ought to be, and we also gear up our metabolism to help deal with the energy because we have to expend energy to metabolize our food. And so in a world without artificial sweeteners, what would happen is that a sweet taste would be a really good predictor that sugar is going to show up, and so some of our responses would become conditioned. This is basic pavlovian or classical conditioning, the stuff that Ivan Pavlov was studying in the early 20th century.

DrMR: Right.

DrSS: So we know that is those kinds of responses get learned, get conditioned, that there are consequences if we interfere with how good a predictor the signal is. So the idea is that you taste something sweet when you get an artificial sweetener, you taste the sweetness, but your body doesn’t get what it’s expecting, and that then goes on to have consequences for when you get real sugar, because now when you get real sugar, your body can’t appropriately anticipate what’s going to happen because its experience tells it, “Sometimes I get sugar when I taste this, and sometimes I don’t get sugar when I taste this.”

DrMR: Right.

DrSS: “So I’m not going to ramp up my metabolism quite as much. I’m not going to release as many hormones. I’m going to wait and see what happens.” And that kind of delay, that lag, or that kind of suppression of those physiological responses in the short term can lead to things like high blood sugar levels, hyperglycemia, and over the long term we think could be contributing to some of the kind of big negative health consequences that people who drink diet soda seem to be at increased risk for.

DrMR: Now, does part of this have to do with the fact that the… I know in some of the literature it seems that when children ingest artificial sweeteners, they tend to kind of reduce their calories in correspondence with how much artificial sweeteners they intake, but in adults it doesn’t seem to have that effect. If that is true, do you think that part of this has to do with various environmental and metabolic factors in adults that cause them to have a loss of their caloric control, and the sweeteners just are kind of pouring gas on that fire?

DrSS: What people actually do when you give them sweeteners, to answer that question really clearly, the literature is kind of a mess.

DrMR: Right.

DrSS: It sort of depends on exactly how you ask the question and of whom you ask the question. I think it’s safe to say that I could probably find an individual paper that would support any hypothesis you wanted it to!

DrMR: Mm-hmm.

DrSS: So that just means that it certainly could be the case that children show different responses because their experience has been different than what we see in adults, but we also know that—and this is one of the hard things about studying control of food intake, in particular, in humans—there are so many influences that are likely not directly related to physiology. So the amount we consume depends on how big the plate is and how much food has been put on it. That’s what makes it tough to kind of say, “OK, how do all these factors get put together over the long term?”

DrMR: Right. I completely agree, and that brings up a point I’d like to come back to in just a second, which is how some of these confounding variables have been attempted to control for in some of the studies.

But before we talk about that, I’d like to talk a little bit about maybe some observational studies and then a little bit about the interventional studies. And I agree with the comment you made earlier, which is the literature is a bit of a mess, and we can find studies showing artificial sweeteners are “maybe good,” some showing that they’re maybe bad, and that’s where I really enjoyed your paper because you went through the process that I try to go through, which is weighing the body of evidence at large and trying to see what the overall trend might be when we look at all the data rather than just taking one study and using that to support a certain position.

With that in mind, I know you discuss in your paper some of the observational studies that regarding weight gain, it looks like artificial sweetener intake is observed to correspond with weight gain. We don’t really have causal data—and please correct me if I’m wrong when I finish—but weight gain seems to correlate with increased artificial sweetener intake, and artificial sweeteners and sugar sweeteners tend to have the same risk for metabolic syndrome, type 2 diabetes, hypertension, and cardiovascular disease. Any commentary on that?

Artificial sweeteners – weight gain and health

DrSS: Right, so certainly there are a number of observational studies, especially that have been published over the past 10 years or so now, that have really demonstrated that people who drink typically one or more diet sodas a day—and I focus on diet sodas primarily because that’s where most of the data are, that we’ve become increasingly aware of how problematic the amount of sugar-sweetened beverages that we consume actually are for our diets. So as scientists have started to look at what are the risks of drinking so much soda, they’ve looked at sugar-sweetened beverages, and a number of those studies also looked at artificially sweetened beverages, diet beverages, and what was surprising to me is that even though I sort of had this idea in the back of my head based on our animal work that this could be a possibility, it was surprising to me the number and the consistency with which people who regularly drank diet sodas really did end up having increased risk levels that were very similar to what was being seen with sugar-sweetened beverages, so as you mentioned, increased weight gain, increased risk of type 2 diabetes, cardiovascular disease, hypertension, and stroke. The big difference and where the real contention comes from, I think, right now, outside of people who are employed by the food and beverage industry, you won’t find many scientists who will argue that sugar-sweetened beverages are not problematic. There’s a general consensus that drinking a sugar-sweetened soda every day is just not a healthy decision.

DrMR: Right.

DrSS: But when you get to the artificially sweetened beverage data, people will, in fact, recognize that those associations are there, but the tendency is to want to say that that association is that people who are already unhealthy, overweight, at risk for these diseases, they’re the ones who are drinking the diet sodas, and so that’s why you see those outcomes emerge. And in reality, we can’t rule out that as a relationship that certainly could be happening, but in many of the studies, even when you correct for things like people who drink diet sodas do, in fact, tend to be heavier than people who don’t drink diet sodas, or at least they have higher BMIs, they may have different family histories, but even when you adjust for those things in your mathematical models, we still see in a number of instances a significant increase in risk in people who are drinking diet sodas. So I can’t argue using the observational studies that there’s a causal link there, but we have to be careful not to throw away the causal link because it doesn’t seem to make sense to us that it could go the other way, and that’s really what kind of happens.

So the data are definitely clear. The interpretation of the data, I think, is much less clear. And again, that’s really where going to experimental models to figure out, is there any mechanism that could provide a causal link, is there any way this could actually happen? If you can’t find a mechanism to explain it, then you sort of say, “OK, it must just be that unhealthy people drink these sodas and that’s what we’re seeing.” But when we start to find evidence for not just one, but a couple of different potentially plausible mechanisms, then we have to be much more cautious about throwing away those risk data.

DrMR: I agree completely, and you took the words right out of my mouth, which was, you know, it’s certainly possible that an unhealthier population of people, people who are heavier, people that have more diabetes, those could be the group of people that are consuming more artificially sweetened beverages, and so we could have a biased sample when we’re looking at these observational studies, but as you pointed out—I’m so glad that you did—we’ve done our best, at least from these studies that I’ve examined, to try to control for those factors, like weight at baseline or diabetes status at baseline, and that doesn’t seem to really be skewing the data. So I certainly think it pushes the observation taken from these studies a little bit more in a causal direction, but maybe that’s a good transition point to some of the interventional studies, because we do have some prospective interventional studies and some interesting findings there.

DrSS: Right, and I just want to make sure to point out that in none of the studies, when you sort of correct for these baseline factors, in none of these long-term studies, the observational studies, in none of those do we actually see a reduction in risk with diet sodas.

DrMR: Great point.

DrSS: So no matter what you do, at best you don’t see the risk go up, but you never see it go down, which I think is telling.

DrMR: Right.

DrSS: It certainly suggests to me that simply switching to a diet soda is not magically going to improve anybody’s health outcome.

DrMR: Right. I agree completely. I’m so glad that you made that comment. And, yeah, I’d love to get your take on the interventional studies, and the San Antonio longitudinal study (2a Trusted SourcePubMedGo to source) is also a really interesting one that I’d love to get your commentary on. What are your thoughts on what we can glean from looking at the interventional studies in this area?

Interventional studies on artificial sweeteners

DrSS: Again, the individual studies, they’re really hard to do in people. This is just the bottom line because unlike my subjects, where I have complete control over them, people don’t always do what you want them to do. So there are a few recent studies that have been done and a couple of them that I think are well done studies. There’s the choice study that compared groups of people who were interested in losing weight, and these are all people who were regular consumers of soft drinks, typically sugar-sweetened soft drinks, although many of the participants were consuming both regular soft drinks and diet soft drinks or using artificial sweeteners as well as sugar. Because it’s a human population, it’s messy to start with.

DrMR: Sure.

DrSS: And what that study really showed was that they had two intervention groups, one where the recommendation was to switch to diet soda, a second one where the recommendation was to drink water, and a third intentional control group where they got just sort of standardized advice without any specific intervention focused on beverages. The good news is that all three groups lost weight. So what we know is that people can, in fact, lose weight. We’ve known this for a long time. But there was really no advantage of the diet soda intervention—or the water intervention, for that matter. The amounts of weight that were being lost were very similar across the three groups. So those data say to me that someone who shifts from regular sweetened sodas to diet sodas is not necessarily going to have a better outcome even when they are trying to lose weight.

And that study was particularly interesting because that group published a second paper where they reported on what the diet beverage and water groups were actually eating and drinking before and after the intervention. What was sort of shocking to me was that the diet beverage group had worked their way up to consuming over 900 mL of diet soda a day, almost three cans of soda a day, and they were still consuming the same overall amount of sugar as the group that had been given the water intervention. So adding 900 mL of diet soda doesn’t actually help you reduce your sugar intake any more, which wasn’t necessarily surprising to me, but that’s kind of the argument that you hear: “Well, if you switch to diet soda, you won’t want as much sweetener. It’ll help kind of satisfy your sweet tooth.” And those data certainly don’t really support that argument.

DrMR: Right.

DrSS: They don’t necessarily make you consume more sugar, but they don’t seem to help you consume less sugar.

There’s another study that was done in adolescents where there was, again, an intervention to try to help overweight adolescents not gain quite so much weight over the long term, and the intervention was to suggest or strongly recommend the reduction of sugar-sweetened beverage intake. And in that study, what they did was they pushed unsweetened beverages. They didn’t tell people they couldn’t consume artificially sweetened beverages, but they strongly recommended the unsweetened beverages, and the data showed that was an effective intervention but that both groups kind of cut down on the amount of sugar-sweetened beverages they were consuming, and that was a positive thing, and the major difference between the two groups was that the intervention group really increased the amount of water and unsweetened beverages they were consuming. So again, it’s hard to use those data to argue that the diet soda approach was effective because that’s really not what happened.

And then unfortunately there are some data that have been published more recently from a study that was really just not well designed—it was highly confounded—that claimed that diet soda was more effective than water in producing weight loss. But I think that because of the number of confounds in that design, it’s really hard to conclude anything about what was actually going on.

DrMR: Gotcha. I look at this where we have this large amount of data suggesting that the artificial sweeteners, if at best, tend to do nothing, and then we have a fairly strong amount of observational data showing that there may be a downside to these artificial sweeteners, so that makes me skew more on the side of caution with them. If you can maybe give your unofficial kind of thinking on this, do you lean in that direction also? Or how do you interpret all this if someone were to ask you, “Hey, what would you tell your cousin to do?”

Dr. Swithers’ opinion on the health of artificial sweeteners

DrSS: You kind of hit it right on the head there. That is my perspective on this. We have no good data that these are helpful for anything. I have not seen any clear evidence that artificial sweeteners actually promote better health outcomes. And we are now starting to get more data, especially from these long-term studies, that the people who are drinking diet sodas end up with worse health outcomes, and we have some evidence for the kinds of mechanisms that could produce those outcomes, so I’m not sure why we would tell anyone that this is a good strategy. It’s always going to be the case that the advice depends on what you’re comparing it to. There are interventional studies in people where it’s clear that if you take a person and you ask them to add an extra liter of soda to their diet and you do this for 6 to 10 weeks, if that’s a liter of sugar-sweetened soda, you’re going to get a much worse outcome than if it’s a liter of diet soda. That’s clear. So it’s clearly the case that large quantities of regular soda over even a short term are a terrible idea. So diet sodas are better than some things, but does that mean that they’re healthy choices? That’s where there’s no evidence. I’m not sure I’ve told my cousin this, but I’m pretty sure I’ve told at least one of my aunts and uncles!

DrMR: Sure!

DrSS: There’s really no data to suggest that these are healthy outcomes on a regular basis. In many ways, I think, we find ourselves in this situation because we’ve lost sight of how we ought to be using these products. We’re not supposed to be drinking sweetened beverages every single day, much less with every meal, and most of us wouldn’t sit down to our dinner and pour out a bag of candy on our plate.

DrMR: Right.

DrSS: But if it’s a sweetened beverage, for some reason, it’s different in our heads. That’s allowable. And when we get to the point where we do this every single day or every single meal, that’s where we run into the problems. The other way to think about it is, if we’re using these products the way we ought to—every now and then—as a treat once every two or three weeks, it may not matter whether it’s a sugar-sweetened or a diet beverage.

DrMR: Right. Excellent point, yeah. That’s a great, great point.

Artificial sweeteners and the microbiota

DrMR: Now, what about this term that, I believe it was Suez, if I’m pronouncing that correctly, they had a paper (3a Trusted SourcePubMedGo to source) in Nature last year that termed something known as “artificial sweetener responders,” and I thought that was very interesting where they found people with certain microbiotas would respond negatively to artificial sweeteners, and they proposed a potential microbiotal angle to predict if you would have this negative, compared to maybe neutral, outcome. Do you have any thoughts on that?

DrSS: Yeah, I mean, I think that that paper was really very interesting for a couple of reasons. There was an earlier study that had suggested in rats that sucralose, the sweetener in Splenda—actually in that study they used Splenda, so I’ll just say Splenda rather than sucralose—but they showed some evidence in rats that rats given Splenda showed some evidence of increased weight gain as well as some disturbances in their microbiomes. The Suez paper really did a nice job of kind of exploring multiple different sweeteners and showing really fascinating things and things that I think that we probably need to pay more attention to than weight, like changes in glycemic responses.

And the idea that not every individual is going to respond the same way is also something that we need to be paying a lot more attention to. In our own work, we actually see very big sex differences in our rats respond to sweeteners, and that’s something that’s really not very well explored in the human literature. For lots of reasons, much of the interventional work in humans in nutrition is done in women. It’s not remotely uncommon to find samples of a hundred individuals and maybe 15 of those are men, which is kind of the opposite from virtually every other medical question that’s ever been asked. Women are overrepresented in the nutrition interventions. So it’s not surprising that there would be individual aspects of someone’s physiology—their genetic phenotype, their microbiome—that could predict whether or not they’re going to show these negative responses. For me, one of the things that was fascinating about their study was how quickly those effects showed up.

DrMR: Right.

DrSS: It does not take much time, and that’s consistent with what we see in our studies as well. This is not something that actually takes a long time to produce this negative outcome, so if we’re seeing this within the course of a week, imagine what happens when you’ve been drinking diet soda for 10 years.

DrMR: Absolutely, and two thoughts were running through my head as you were saying that. One, if you’re using these things in a moderate application, like you mentioned a moment ago, it probably won’t be a big deal, if it’s occasional use.

DrSS: Right.

DrMR: But also it reminds me of the San Antonio longitudinal study, that they tracked a large group of participants prospectively forward through time, and they found a dose response to the more artificial sweeteners consumed and actually the increased waist girth or circumference in these people, and I thought that was a really interesting study. What are your thoughts on that study?

DrSS: That one is really important because they did not find an association there with BMI or weight, and that’s important because that’s an older cohort, and one of the things that happens as people age is that their weight can go down even as they’re becoming less healthy.

DrMR: Right.

DrSS: There’s been a tendency for lots of us to focus on weight because it’s easy to measure and it’s what many people will articulate that they care about, but it’s also really important to understand that we should only care about somebody’s weight to the extent it tells us anything about their health outcomes.

DrMR: Absolutely.

DrSS: So, yeah, that study, I think, is a really important one because it does suggest that people who are using these soft drinks, they’re putting on weight and they’re putting on weight or fat in a way that is really strongly correlated with negative health outcomes. Abdominal fat is not the kind of fat that you want to put on. If you have a choice, that’s not where you want it going.

DrMR: Exactly.

DrSS: So I think that what we’re going to start seeing is that we’re going to keep seeing more and more of these studies that try to look at these health outcomes, and as I said, I’ve yet to see one that suggests, especially over the long term, that there’s a real benefit from using artificial sweeteners.

DrMR: Exactly, and I think the person that is really done a disservice here is the person that is trying to lose weight, switches over to an artificial sweetener and maybe even has the mindset of, “Well, there are no calories, so I can really just kind of go nuts.” And while, again, not definitive, there’s certainly some evidence starting to present itself that these things certainly may have no benefit, but may have some detriment, and that’s the person I hope this really reaches and hopefully sways to rethink their use of these things.

DrSS: Right, and I think that people have really been sold the message by the beverage industry that these are, like I said before, kind of magical, that you just switch these in and automatically everything is going to be better, and we clearly have no evidence that that is actually true. We also know that over the short term, people can actually do things like count calories and read labels, but we also know that that’s exhausting and really not a very interesting way to live your life. It’s not fun to track every morsel that goes in your body for every moment, so if these sweeteners have a possibility of actually making it harder for you to deal with the real sugars that you do get, then where is the advantage of these products? And for many of them, I mean, we certainly don’t know at this point. It kind of depends on which particular mechanisms are operating, but they may not all be equal. Some of them may be producing different outcomes. There’s a mouse study that suggested that aspartame also could have some influence on the ability to regulate blood sugar independent of any weight gain effects, again possibly by affecting the microbiome. We’re still at a place where there’s a whole lot we don’t know about what the consequences of most of these sweeteners actually are, certainly not over the long term.


DrSS: That reminds me that kind of the newer sweeteners that have been approved are stevia-based sweeteners, and just because they’re not artificial doesn’t necessarily mean that they’re going to be better choices. We still don’t know much about those. Again, over the long term, the data just are not available in terms of what are the consequences of the stevia-based sweeteners, which are natural to the extent that you can call something that’s been highly concentrated and extracted from a plant product natural. They’re natural from that sense.

DrMR: Right.

DrSS: But it’s not about natural versus artificial, which is what I think sometimes people can get hung up on. It’s really about what are they doing once they get into our bodies, and for many of them, what we don’t know is much greater than what we actually do know.

DrMR: You took the next question right out of my mouth, which was about stevia, so I’m so glad that you said that, and I love your point about natural versus synthetic or what have you, and I think it is important for people, especially a lot of the listeners, to remember just like you said, that just because something is natural doesn’t mean it’s going to be OK. I mean, cocaine would be an example of that. Yeah, that’s natural, but—

DrSS: Yeah, well, cocaine has been really over-vilified! I will tell you this. There’s evidence from animals that if you give rats a choice of a cocaine injection or a little bit of saccharine water, most of the animals will choose the saccharine. But my example, I tend to like to say that anthrax is natural!

DrMR: Right. There you go!

DrSS: There’s no debate than anthrax isn’t healthy! That’s not a healthy choice for anyone.

DrMR: Right, and so what I’m hoping people will take away from this with stevia is, yes, just because stevia is natural, the same rule may apply, where if you’re using it every day or three or four times a day, that may not be a great idea. We still don’t know. We certainly don’t have near the level of studies for the other sweeteners that we’d like to have for stevia, but I would exercise some caution there because who knows? Maybe once we have a few long-term follow-up studies with stevia, we may see some of these same problems emerging.

DrSS: Right, and again, there are small studies. There’s a study that a colleague just pointed out to me a few weeks ago that there are some of the indigenous people in South America who use concoctions of stevia leaves as contraceptives.

DrMR: That’s right. I actually did hear about that. You’re right.

DrSS: Yeah. Plants are very complex things, and when we extract things out of them, we may think that we know what we’re doing, but we don’t always have the outcomes that we expect. The way I like to sort of think about this is that we should be focusing on eating and drinking foods, things that are actually so much less heavily processed than what we typically consume or what the kind of average American diet has actually been. I know that we as a population consume way too much sugar, but a little bit of sugar may be a better choice than a ton of artificial sweetener—but it has to be a little bit. A ton of sugar is clearly not a good decision.

DrMR: Mm-hmm. And I don’t know if it was in your paper or another group of researchers, but they essentially had the recommendation of if you’re needing a sweetener, use a small amount of maybe some honey or some fruit juice—or even a small amount of sugar—rather than some these man-made or highly isolated chemicals that we still know very little about, and that seemed like a fairly prudent recommendation. I know they mentioned honey, fruit juice… I’m not sure if they actually recommended sugar because that would be concentrated.

DrSS: Well, honey and sugar are fairly similar to one another. The other thing that people don’t often recognize is that the way we think about food is we tend to think that we eat what we like, but really we like what we eat. We get used to things having a certain level of sweetness or saltiness or fat, and if we make an effort, it is possible to shift those preferences. It takes effort, but simply cutting down, you know, if you normally put two teaspoons of sugar in your coffee, cut down to one, and eventually you’ll figure out, “Wow, you know what? Two teaspoons just tastes way too sweet to me right now.” We can make some of those adjustments, but it takes time and effort. And certainly our food environment, the way we’re marketed to for these processed products does not make that easy. It’s certainly much easier to go out and find something that has had a ton of sugar or other sweeteners put into it for us than it is to kind of make these better choices.

DrMR: Mm-hmm. And it’s easier, I think, for a food producer or manufacturer or restaurant, what have you—it’s easier for them to have kind of crappy food and then put a bunch of sugar in it and make it taste good. I’ll just share my own experience with coffee. Once I started drinking different espresso drinks, I’d go to Starbucks and get a mocha macchiato or one of those sweetened drinks. And then I went through the exact process that you recommended, which I think is a brilliant recommendation, and I would just get a shot of espresso and I’d add some cream to it, and I quickly started to notice that at certain places, some of the big chains, the espresso just tasted burnt.

DrSS: Yep.

DrMR: And so I found a local coffee shop that was run by just a group of hipsters that were super into quality. I would have a little bit of cream with their espresso, and it was totally different, tasted wonderful, and now I don’t need any sugar at all and I still have the same amount of enjoyment. So I love what you said, which is, we like what we eat. Yeah, that’s a great point.

Beverage industry advertising tactics

DrSS: Yeah. Unfortunately it requires a lot of time and energy to do that. One of my frustrations at this point is just the amount of sort of saturation advertising that we’re all getting that leads us to kind of want to have these foods and beverages that are really not so good for us. My kids are in high school, and their recycling bins in their high school are donated by a major beverage producer, and they are shaped and colored like that beverage producer’s main product, and it makes me insane!

DrMR: Oh, man.

DrSS: As a parent, I don’t want my kids getting marketed to anywhere, much less in their school. I make clear analogies. For me, the analogies between the tactics of the tobacco industry and the tactics of the beverage industry are very similar. “Market this stuff to as many people as possible. Make this seem like just a phenomenal thing that everyone is doing. Use celebrities to make it cool to consume this product.” And I think that we kind of need to wake up and understand that there’s certainly personal responsibility. Everybody needs to be making these decisions, but those decisions are strongly influenced by everything we see and hear. It goes even beyond just putting recycling bins in schools.

DrMR: Sure.

DrSS: I think it’s important for people to be more knowledgeable about what the science actually says, and I feel comfortable saying that the real recommendation is that we need to, in general, reduce the amount of sweeteners we’re using, whether they have calories or not. But we also need to be paying attention to, how are people making these decisions? How easy is it to find good food and beverages that are going to be tasty and satisfying and aren’t going to cost a million dollars? I like to say that I have all the knowledge, I actually have a fairly flexible schedule and a reasonable amount of income, and I still make terrible choices because they’re easy sometimes.

Dr. Swithers’ worst health choice recently

DrMR: Well, that’s a great segue into, what is the worst health thing that you’ve done lately?

DrSS: Yeah, so on days when I’m very busy—like today—I mean, I really do make terrible choices. I think today I’ve had three of those sort of snack-size candy bars and a bag of chili cheese fritos to eat. That’s been my diet so far today. What that means is that for dinner I will not continue that pattern! But you know, that’s what it was. I try not to eat like that every day, much less every meal, but sometimes it happens, and what this hopefully means is that tomorrow when I leave the house to go to work I will bring food with me rather than relying on the vending machine down the hall, which is convenient.

DrMR: That’s always a dice roll. Yeah, I know. Awesome. Well, Susie, thank you so much. This has been a terrific call. I think you already gave us your closing thoughts. You just kind of gave those, so I guess if people wanted to hear more from you, where could they track you down or follow you?

DrSS: I’m on Twitter. My handle is @SusiePsycho, although I’m not particularly active on Twitter. I tend to retweet other things I find interesting. And I’m at Purdue. I’ve not been good about keeping up my website, but googling me tends to find what I’ve been up to pretty easily.

DrMR: Gotcha. OK, fair enough. Cool. Well, thank you again so much. This was a great call. I really appreciate what you’re doing with your research, and if you have any new findings that come your way that you’d like to discuss, please let me know and we’ll have you back on.

DrSS: OK, great! Thanks a lot.

DrMR: All right. Thanks, Susie.

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