Jim Hill: Welcome to “Weight Loss And…”, where we delve into the world of weight loss. I'm Jim Hill.

Holly Wyatt: And I'm Holly Wyatt. We're both dedicated to helping you lose weight, keep it off, and live your best life while you're doing it.

Jim Hill: Indeed, we now realize successful weight loss combines the science and art of medicine, knowing what to do and why you will do it.

Holly Wyatt: Yes, the “And” allows us to talk about all the other stuff that makes your journey so much bigger, better, and exciting.

Jim Hill: Ready for the “And” factor?

Holly Wyatt: Let's dive in.

Jim Hill: Here we go! Welcome to another episode of “Weight Loss And..” I'm Jim Hill along with Holly Wyatt. Holly, today we're going to talk about ultra-processed foods. Have you heard of these?

Holly Wyatt: I have. I don't know that I can define it. I don't know what I know what it is, but I have heard of it.

Jim Hill: Well, I'm the same. I'm really confused. I go to the grocery store. I'm not sure exactly what I should avoid. And so you and I are both confused, but fortunately, we have a guest today who's going to clear up all this confusion. I'm really happy to introduce our guest, Dr. Richard Mattes. Rick is a distinguished professor of nutrition sciences at Purdue University. This guy is a famous nutrition researcher. I've known Rick for a long time. He understands food. He understands nutrition, and he has a very reasonable approach to it. So he is going to sort us out, Holly. Rick, welcome to “Weight Loss And..”.

Richard Mattes: Well, with that buildup, I'm intimidated, but I'm happy to be here.

Jim Hill: So Rick's research is focused on taste, hunger, satiety, food preferences, and regulation of food intake. Now, Rick has a PhD in human nutrition, but he's also a registered dietitian. Rick, just take a second and sort of tell us how you got to where you are.

Richard Mattes: So I planned on a career in dietetics, started in that direction, then went on to graduate school and at the time, WIC was just starting the Women Infant Child Feeding Program. And I was intrigued by that and thought I would go into program evaluation. But started down that road and then attended a lecture from a guy in psychology who talked about taste and smell and nutrition. And it was one of these epiphanies. I changed my committee midstream and started in a whole new direction and haven't looked back.

Jim Hill: I love that. It's like being in science is sort of following what interests you, and you find a thread over here and you pull on it. That's fabulous, Rick.

Holly Wyatt: So I will kind of kick us off. Rick, so many people I think are being told to reduce their intake of ultra-processed foods. And like I said, I'm not even sure I can define that. So can we just start by you saying, what do we mean when you say ultra-processed foods?

Richard Mattes: To give you just a brief history of this concept, it started with the idea that the functional properties of foods were dictated by their physical form, its physical properties.

And so if you mechanically disrupted that in some way or thermally disrupted that in some way, you could alter the bioaccessibility of nutrients and so have an impact on nutrition. And all that was very squarely in the world of food science and nutrition science. And there were clear definitions. But this concept quickly evolved. The next iteration included in the definition foods that had certain ingredients added to them, like added sugars, added salt and added fat. And so rather than being just a processing, it was now a formulation. It expanded to include formulation because it had different ingredients as well as problematic properties of it. But then it evolved again and started and included unintentional food additives like pesticides and preservatives and compounds that are formed when foods are cooked, like acrylamide. So those were viewed as problematic.

And now we're actually at a stage where it's moved one dimension. And when you talk about ultra-process foods, you're talking about foods that have some impact on the environment as well. So sustainability issues. And so when you try to come up with a definition that covers this gamut of issues and concerns, I think you're hard-pressed to come up with a single unifying definition. And that's where we are. And that's a big problem because if you can't define the phenomenon, how do you measure it, and how do you correct it?

Jim Hill: I love that because I have trouble defining it. Is there any science here, Rick?

Richard Mattes: Interestingly enough, so there's one classification system called NOVA, which doesn't stand for anything. It's just the acronym that's used. And it's the primary one globally that people talk about.

But there are others. The World Health Organization has one. The International Food Information Council has one.

Researchers in North Carolina have one. So there are different definitions of processed food and ultra-process food. And none of them agree with each other. Nor do they agree on their health implications. So one will correlate with obesity. Another will correlate with blood pressure. Another will correlate with blood glucose levels. And the other ones don't. So it's a poorly defined field.

Holly Wyatt: So I don't feel so bad now that I couldn't define it because in a simple way, can you kind of give our listeners something they can think about when we say ultra process, realizing it's not going to be perfect because there is no consensus.

Richard Mattes: I hesitate to say this, but they, most simply, it's not far removed from the colloquially used concept of junk food, which also is not defined in any scientific realm, but it seems to connote something that people resonate with that they think they understand it.

Jim Hill: Well, that's my question, Rick. Is telling people to avoid ultra-processed foods? Is that giving them a strategy over and above the other strategies that we tell them about diet and avoiding foods high in sugar and high in fat and so forth?

Richard Mattes: No, actually, I would argue just the opposite. I think that this concept of processing and ultra-processed foods in particular, which incidentally is just an inflammatory terminology to capture people's imagination in my view, because when you read, for example, the NOVA definition, we'll talk about not just all those processes that I referred to a moment ago, but also the purpose for which foods are processed, which takes it out of the realm of science and into the world of business and economics. Those who are very concerned about the consumption of these foods are also very concerned about the food industry and its role in promoting poor dietary habits in the population. So there is a political dimension to this concept as well.

Holly Wyatt: So does that mean it means that something was processed like pasteurized to prevent infection, that might be seen as different if it was processed to help the food company get it into a package to sell more? Is that the kind of what you're saying?

Richard Mattes: Well, it would be nice if it was as straightforward as some processing is helpful and some processing is not helpful. But those lines are very blurry. And so it's not possible to use that as part of the definition. But to answer your question, Jim, I think it's worse to try to use this concept because it's internally inconsistent. So, for example, one of the concerns is that highly processed foods are high in added sugars. And so the logical extension of that is it would be desirable to reduce the sugar content of foods. Well, one way to do that while maintaining the palatability, and the acceptability of foods is to use low-calorie sweeteners. However, by this definition, if food contains even a nanogram of a low-calorie sweetener, it's considered ultra-posthuman and has to be avoided.

Jim Hill: We just did a segment on that, Rick, and concluded that people shouldn't worry about those. If it makes you happy to have something sweet with non-cleric sweeteners, go for it.

Richard Mattes: Right, especially given that by definition, they're there in very, very small quantity. But even another example is they're concerned that these ultra-processed foods are digested quickly. So the energy is absorbed quickly, particularly the glucose. So it raises blood sugar levels and so on. Well, one way to moderate the rapid rise in blood sugar is to have a more balanced macronutrient mix. In particular, fat slows the absorption of glucose. However, one of their concerns is added fat. And so they're worried about elevated blood sugar. But if you make a product that has some helpful fat, added to helpful fat, it makes it ultra-processed and unacceptable.

Jim Hill: Oh, my gosh. And we wonder why consumers are confused about nutritional advice. But Rick, if I go in the grocery store, and I'm saying, “Hey, I want to avoid ultra-processed foods,” is there any way for me to know what to avoid as just a general consumer?

Richard Mattes: Well, so those who are proponents of this concept have come up with a solution to that question. And they say any product that has more than five ingredients is probably ultra-processed and should be avoided. The problem with that is that if you have a nutrient-enriched or fortified product, that is, it has added minerals or vitamins to it.

That's going to violate the principle. And those added nutrients are a very important source of nutrition for many people. And so, it's one of some why this concept actually has a very tangible risk associated with it. If you take out all these ultra-processed foods from the diet, you are going to have a substantive negative impact on diet quality for people who rely on convenience foods.

Jim Hill: That's interesting. One of the things I was reading about this and one of the examples people use, if you eat a cookie baked at home, that's OK. But if you eat one, you buy in a store, that's not OK. That seems a little crazy to me. But Rick, before we get off this, let's talk about food processing in general. For some people, that has a negative connotation. But food processing is a wonderful step forward for our food supply, right?

Richard Mattes: Absolutely. It has dramatically improved the safety of the food supply by adding preservatives different types of thermal processing and so on. We have made a food supply that can be stored for some time and remain safe.

And so it's accessible to people that don't have the means to shop frequently and so on. It also reduces food waste. If a preservative is added to a food, it's automatically ultra-processed and should be avoided. We're in fact to take those foods out. We would be forced to waste a lot of food if we don't want to eat spoiled food. And so, ethically, that too poses a serious challenge to this concept.

Holly Wyatt: What about weight loss? So a lot of our listeners are trying to lose weight. Do you have any kind of message around ultra-processed foods or processed foods in terms of helping them manage their weight? Should they avoid them or does it matter? What are your thoughts on that?

Richard Mattes: Well, if you'll allow me, let me share with you my interpretation of the science as it exists presently. There are sorts of three pillars of science that one would hope would come together to formulate dietary guidance and certainly to set national nutrition policy. So you would like to have some epidemiologic evidence that tells you who's at risk, what's the scope of exposure and if is there a plausible hypothesis of importance here. And in this case, there is an abundance of epidemiologic evidence that shows that there is a positive association between consumption of ultra-processed foods and increased body weight. It's unequivocal.

It's been replicated many, many times. There is a positive association. Now, let me emphasize association and not causation.

We can talk about that in a moment. This evidence is consistent, but I wouldn't say it's overly strong or compelling. The effect sizes are quite small in many studies and in many of the meta-analyses that have been published. The effect size is an increase in risk of about 2%, 4%, 6%. We have many things that have been identified as contributors to positive energy balance and weight gain that have effect sizes much greater than that. Just watching television or not exercising in the gym is a much bigger effect size than that. So there is a lot of concern, a lot of hype about this epidemiology, but in point of fact, it's positive, but it's indicating it's not a strong effect. OK, but it's positive. It's significant.

And that's what's driving the interest here. So the second branch is you'd like to have clinical trials to establish causality. And in this case, we have exactly one, one published study that was designed to test the effects of ultra-processed food consumption on food intake and body weight. And that one study, I should preface this by saying I applaud the researchers for conducting the first study and starting to deliver science on this issue. But we also have to be a scientist, critical, skeptical of any study and certainly not willing to believe the results of any one study to conclude. So there are limitations to this one study. And one is they show that over a two-week period, which is nutritionally a fairly inconsequential period in a study of 20 people, which is a very small sample size, that when on a diet composed largely of ultra-processed foods, and when I say largely, I mean over 80 percent of energy was from these foods, no population on the planet consumes that level. So this is a proof of principle study rather than a reflection of reality.

But that's fair enough for a first study to do proof of principle. So what they found was that energy intake was about 500 kilocalories greater on the air during the two weeks that ultra-processed foods were consumed compared to when minimally processed foods were consumed. However, their data, and they honestly report in the paper that there was is a statistically significant trend for reduced energy intake over time. And if you look at the magnitude of that decline in energy intake, if the study had been conducted for even a week longer, it would have vanished.

Jim Hill: Ah, novelty effect. Right. It's the cruise ship effect.

Richard Mattes: You put yourself in a novel environment with unlimited palatable food and initially you over-indulge.

Jim Hill: Turn your five-year-old loose in the grocery store and see what they eat.

Richard Mattes: Right. So it's a transient effect and rather brief at that so we can all absorb a transient effect without long-term health consequences. But the other thing that troubles me is that the conclusion was that it was the ultra-processed foods that were problematic, that it was this processing that is the culprit here, the mechanism. However, the increased energy intake was only seen during breakfast and lunch. It wasn't at dinner or during snacking. If it was really processing, it was the ultra-processed and minimally processed at those other eating events too. So that says it's something more about an eating pattern but not related to the processing itself.

So my take is that in the one clinical trial that has been published, the evidence are not strong in support of this concept that processing is the property that's responsible here. And that takes finally to the third arm of science, which is mechanistic studies. If we're going to believe that something has a real effect and we would want to intervene then to correct it, we have to understand the mechanism. To give you an analogy of how important mechanism is, I use this, Julie Jones I think may have been the one to first voice this, but I think it's so good. If you knew nothing about the effects of alcohol on fine motor control and cognitive processes and so on, I think none of your listeners here would doubt that there's an association between drinking cocktails and traffic accidents.

Probably no argument there. But if you didn't understand the mechanism, you'd be equally likely to blame the mixer as well as the alcohol. So we have to understand what part of an intervention or an exposure is the culprit here. And that's why a mechanism is so important. And we've recently conducted what we hope was a pretty encyclopedic review of the literature to identify mechanisms. Around about 16 are cited in the literature, but there isn't science for a single one of them to substantiate them. It's just speculative, it's hypothetical, it's plausible, but there is no science yet to substantiate any mechanism.

Jim Hill: Wow, that's amazing. One of the other things that bothers me a bit about this Rick, I'd love your opinion on this, it's sort of in some ways makes people feel guilty if they aren't growing food in their backyard and baking bread from scratch and everything. It's sort of like a moral issue that if you were a good mom or a good whatever, you wouldn't be eating all this food from the middle of the grocery store, you would be doing it yourself. And that's just not feasible for so much of the population.

Richard Mattes: It's not clear that it's feasible even on a sort of global basis that we would have a sufficiently abundant and diverse food supply if we relied only on those kinds of agricultural practices. But your point is even more important because the people that, as I mentioned before, some of the people that rely on convenience foods, for example, parent households, need convenience to be able to operate efficiently, to take care of the kids, to get them where they have to go and so on. They don't have the luxury of a lot of time to prepare to shop and to prepare food and clean up afterward and so on. Convenience foods are a real boon to them and these ultra-processed foods are not compatible with that. Food individuals who are food insecure, again, need a food supply that's relatively inexpensive, and relatively stable, and ultra-processed foods are an important component to their sustainability. And if you take that away, they would be in much greater risk.

Holly Wyatt: So Rick, given that what you just said and how important that is, that it's an important piece, plus the lack of data that we just kind of went through, the lack of one study, and why do you think there's been this push to talk about getting rid of not eating, decreasing, whatever, ultra-processed foods? Why has there been such an emphasis on this?

Richard Mattes: Well, you may view me as a cynic. But, this obesity problem is enormous and it's getting worse, and it's very severe. And so we are trying to come up with any explanation to understand it so that we can intervene. For a long period, we viewed it as a metabolic issue, one of energy balance and oxidation of substrate, and so on. We had diets that were based on glucogenic diets, immunostatic diets, and lipophilic, all things.

And it didn't adequately provide an explanation that could be operationalized. And so then we discovered that there were important endocrine factors, the gut peptides, and their satiety properties and their influence on digestion that may be responsible here. And we were enamored with that for quite a period. And we learned some wonderful biology. And of course, now we do have some drugs that have resulted from that science. But those are pharmacologic effects. Those are not, in my opinion, dietary effects. And the dietary, reliance on endocrine control of feeding and energy balance, again, didn't prove particularly useful. And so then we moved into the area of reward mechanisms, moved up to the brain, and how certain foods were more prone to activate reward mechanisms than we talked about hedonic eating and eating in the absence of hunger and so on. And I think that there is a role there.

I think that that's part of the story. But it is not, again, proving to be a useful concept for management. And so out of desperation, we are looking in other directions. And out of the food industry came this concept that we've had it wrong all along. It isn't about nutrients. It isn't about foods. It isn't about eating patterns. It's about processing.

And it's novel. And it has a certain intuitive appeal to it because many foods that honestly should be consumed in moderation are highly processed foods. And so it resonated with people. And I think that's where we are now.

Jim Hill: You and I throughout our careers, Rick, have seen this happen over and over of somebody says, finally, we know the problem here. We know the solution. And I talk about that and always show obesity rates going up and up and up and up.

And none of these ever produced a decline. I think we've got to realize it's never going to be as simple as one thing. And as much as you want it to be about one thing, it's not. This is complex.

It involves things on the diet side, on the physical activity side, in the brain. And I think we have to wrap our heads around that complexity. All right, Holly, what time it is?

Holly Wyatt: It's vulnerability questions. We have to, we have some personal questions that they're hard. Get ready. Get ready. Jenny, do you want to go first?

Jim Hill: Rick, what kind of diet do you follow?

Richard Mattes: Geez, I'm as excited as a bag of nails. To me, the best dietary advice and the philosophy that I try to follow is just to balance moderation and variety.

Jim Hill: Oh, how boring, right?

Richard Mattes: In my view, science is strongest for that perspective. But it is a philosophy that just doesn't have enough appeal to get people interested in it. Everything else has much more appeal, but less science.

Jim Hill: No, I think you're right. I think people do find it, oh, give me something really exciting when, in fact, it's the balance and moderation that's important. And what we try to tell people, you have choices. There's no one way to do it. There's no one diet you have to eat. You balance your food with your activity. You can have some fun with your diet. But I think you're right. I think it's balance and moderation.

Holly Wyatt: I'm going to come out against you a little bit here, Jim, just because I agree with what you're saying. But Rick, have you ever struggled with your weight?

I think people have told me, yes, balance moderation. And I'm like, I struggle with that. That's hard for me. I think it may be easier for certain individuals to say, “Don't eat that cookie, eat one cookie, don't eat the whole bag of cookies.”

But the signals I'm getting are making me think about the whole bag of cookies the whole time. So I think that's why people don't, that balance thing sounds good once again, but isn't always really feasible for people.

Richard Mattes: You bring up a very, very good point. We've been talking up till now about the role of the food supply coming in. We haven't talked about individual variability of people in response to that. And you're exactly right. Some people would, honestly, some people respond very favorably and unfavorably to any of these fad diets. Whatever comes out, there is a certain subgroup of people that seems to work for them. And so I think the way the field of nutrition science is going is presently to have an increased interest in individual variability in responses to a common exposure, a common diet, and so on. And we do have to understand that the most important take home at this moment is to recognize there isn't one diet that is going to work for everybody. There are different philosophies, different approaches, different lifestyles, different genetics, and all of those have to come together to make something work.

Holly Wyatt: I agree with that. I think that's something we're starting to see and understand. And I hope that message is getting out there to the public too. There isn't one way you have got to figure out or start to think about what works for you. And hopefully, we have some science that can help us with that in the future.

Richard Mattes: I think that's part of the beauty of the dietary guidelines. The dietary guidelines emphasize that there isn't one optimal diet. There are many ways to constitute a diet that takes into food preferences, cultural habits, lifestyles, and so on. And many ways will lead to a healthful diet.

Holly Wyatt: So another vulnerability question, what do you think is the most exciting research that you're aware of in this area? Maybe you're doing it, maybe somebody else is doing it, maybe for our listeners. What's exciting that's coming?

Richard Mattes: Whoa. My gosh, there are so many things. My world is sort of focused on set of factors. And just before coming on with you, I was listening to a lecture that was being given virtually at the Monal Chemical Senses Center about taste receptors that are located everywhere in your body. We call them taste receptors because they were first identified in the mouth, and that's where taste happens. But in fact, these receptors are in every tissue of your body.

And they play many, many roles. These receptors turn on whatever kind of cell they are embedded in. So if this taste receptor is in your pancreas, glucose comes in contact with a beta cell in your pancreas, and that taste receptor will release insulin. If it's on an endocrine cell in your intestine and food is coming through your intestine, it hits that taste receptor cell, and it will release CCK, GLP1, all of these gut peptides that influence how nutrients flow through the system, and nutrients are absorbed and so on.

So there is a real revolution in my thinking about how the receptors that we call taste, and it's olfactory receptors, smell receptors too, that these receptors are located in the oral cavity and in the nose, but they're just the very front end of a sequential signaling system throughout the whole GI tract. And it's the coordination of that. We've always known that you have to have coordination throughout the whole system to absorb the nutrients, get rid of the waste, and so on. And there is signaling that goes on step by step as food is passing through. I think there's a lot of information to be gained from that that will be important.

Jim Hill: Okay, Rick, we're going to end with what Holly likes to call pie on the plate, rather than pie in the sky. Is ultra-processed foods something our listeners should worry about in your opinion?

Richard Mattes: I think that they should worry that it is being used to set national policy without adequate science to substantiate its efficacy and most importantly its safety and its ethics. As I said before, there are some very tangible potential adverse consequences of adopting this approach for categorizing foods, calling them good, calling them bad. According to estimates, ultra-processed foods represent about 56% or 58% of total daily energy intake. If we were to accept the recommendations of the advocates of this NOVA system, for example, we would be taking out more than half the foods in our food supply. We don't know what the impact of such a radical behavior change would be.

We've seen it go awry, Jim. You were talking about us being old enough to see trends. Remember when fat was the culprit and the food industry came out with low-fat, everything you could imagine in the grocery store? But as you said, BMI levels kept rising in the population. We were missing the boat because we didn't understand the mechanism.

Jim Hill: I would translate that also to say, stay tuned about ultra-processed foods, but right now it's not going to affect you when you go in the grocery store. You've got other things to worry about, but do stay tuned. Rick, thank you so much for being our guest. We've enjoyed chatting with you. It's been fun.

Thanks so much. We'll see everybody next time on Weight Loss and. Bye, everybody. That's a wrap for today's episode of “Weight Loss And..”. We hope you enjoyed diving into the world of weight loss with us.

Holly Wyatt: If you want to stay connected and continue exploring the “Ands” of weight loss, be sure to follow our podcast on your favorite platform.

Jim Hill: We'd also love to hear from you. Share your thoughts, questions, or topic suggestions by reaching out at [weightlossand.com](http://weightlossand.com/). Your feedback helps us tailor future episodes to your needs.

Holly Wyatt: And remember, the journey doesn't end here. Keep applying the knowledge and strategies you've learned and embrace the power of them in your own weight loss journey.

Jim Hill: And that's a wrap for today's episode of “Weight Loss And…”, we hope you enjoy diving into the world of weight loss with us.

Holly Wyatt: If you want to stay connected and continue exploring the “Ands” of weight loss, be sure to follow our podcast on your favorite platform.

Jim Hill: We'd also love to hear from you. Share your thoughts, questions, or topic suggestions by reaching out at weightlossand.com. Your feedback helps us tailor future episodes to your needs.

Holly Wyatt: And remember, the journey doesn't end here. Keep applying the knowledge and strategies you've learned and embrace the power of the “And” in your own weight loss journey.