Michigan Minds Podcast: Ashley Gearhardt on Addiction to Processed Foods

Jared Wadley:

Welcome to the Michigan Minds Podcast, where we explore the wealth of knowledge from the University of Michigan’s faculty experts. I’m Jared Wadley, lead public relations representative at the Michigan News office.

I’m thrilled to welcome Ashley Gearhardt to the studio. Ashley’s a professor of clinical psychology and an expert with the Institute for Healthcare Policy and Innovation. Her work explores why we’re drawn to calorie-rich, nutrition-poor foods, and what those eating patterns mean for mental health, obesity, health disparities, and other diet-related diseases. She also examines a provocative question, whether certain highly processed foods meet scientific criteria for addiction and what that might mean for food policy at the local, state, national, and even global levels. Ashley, thank you for joining us.

Ashley Gearhard:

My pleasure. I’m happy to be here.

Jared Wadley:

I’ve wanted to talk with you in depth for a while about your work. I’m personally interested in exercise and nutrition. Like many people, I like foods that don’t always make the healthy choice list. I love a thick strawberry milkshake. I savor the taste of hot, crispy onion rings. And I even enjoy an Almond Joy or Snickers bar that I may or may not grab from my boss’s candy dish available to my colleagues.

So let’s start from the beginning. What drew you to study highly processed foods and their impact on mental health and behavior?

Ashley Gearhard:

Yeah, so I actually trained to be an addiction scientist. I was in an alcohol addiction lab and we were learning all about how this product that’s mostly water, most alcoholic beverages are mostly water, that with a little bit of processing and engineering, add a little ethanol, add a little sugar, suddenly it’s something that isn’t about hydration anymore. It’s about craving and altering one’s mood.

And while I’m learning all these things about alcohol addiction, I as a clinical psychologist was training to see patients. And I was in a clinic where I was seeing people with binge-eating disorder and bulimia nervosa and people getting ready to undergo bariatric surgery, a really invasive but effective weight loss surgery. And I was hearing from the clients I was seeing there that they really felt an addictive pull towards many highly processed foods that are now dominant in our food environment.

I actually had some clients who said, “I used to have a problem with cigarettes and I quit smoking, but I picked up this habit now and I just drink soda all day long and I have a whole thing of donuts. And this is happening even though I have unmanaged diabetes and now I’m facing down amputation and blindness.” And so it really got me thinking about whether some of these highly processed foods through those same engineering hedonic processes had actually crossed the threshold from something that nourishes and energizes us into something that can really trigger that compulsive, out of control pattern of behavior.

Jared Wadley:

So that brings us to a big question about your work. When scientists talk about something being addictive, what does that actually mean and how does that definition apply to food?

Ashley Gearhard:

Well, it’s such a good question because it has changed dramatically over history. We used to actually think cocaine wasn’t addictive because cocaine’s withdrawal syndrome doesn’t have a lot of physical symptoms. Alcohol and opiates do. So cocaine isn’t addictive. And then we saw people would consume it compulsively and it’d be ruining their lives and they couldn’t stop.

Then our next big controversy was about cigarettes. Here’s this poisonous plant that they’re able to engineer into something that people, they don’t get high, they’re not intoxicated, but the cravings and the desire for that cigarette, even when we knew how deadly it was, really prevented people from stopping. And actually that is the most deadly addictive drug in the history of human existence.

Well, how we have resolved these sorts of controversies about when a new substance comes on the market that doesn’t look exactly like the drugs that we know are addictive, we usually spend decades and decades debating it, even though people are showing all the classic signs of addiction, that loss of control, the craving, the continued use despite negative consequences, and we miss it for so long.

And so I really look at tobacco as this true benchmark of how we resolved a huge controversy about what does addiction mean if you’re not high, if you’re not going through horrible physical withdrawal. And it really comes down to the idea that people consume it compulsively. They want to stop, they know it’s hurting them and they can’t. It’s that they find it really rewarding and reinforcing. They’ll seek it out, they’ll pay good money, they’ll go out of their way to get it. It alters their mood. It gives you pleasure. It shifts you out of a negative mood and it’s impacting the brain.

We don’t have any really clear biomarker. We can’t look at someone’s brain and say, “Oh, this happened exactly in this brain region, so we know it’s addictive.” That doesn’t exist. We haven’t been able to use that, but we use this sort of cascade of loss of control. It’s all about the mood-altering reward properties and there’s intense craving.

That’s really kind of the scientific benchmark for when we understand when a substance or a behavior like gambling has crossed the threshold where it can be addictive. Now I think it’s really important to understand just because a substance or a behavior has an addictive potential, doesn’t mean that everybody who uses it is an addict, right? Unless it’s going to get you fired, you sneaking it out of the candy jar is not the problem. Most people consume addictive substances like opiates after a surgery or a glass of wine with dinner and they don’t get addicted, but a sizable portion of our society does. Usually when we look at alcohol, it’s about 14% of users get addicted. With cigarettes, it’s about 18%. And the thing that really happens though is that when the environment is totally flooded with it… Right now I feel like this is happening with sports betting.

I mean, I love sports, but I’m so sick of seeing sports betting advertisements every five minutes. There’s going to be a sizable portion who are fully addicted, but when it’s so ubiquitous, a lot of us have this kind of subclinical pull. “Oh, I shouldn’t have had that extra cookie. Oh, I know I shouldn’t have this Coke. It’s bad for my teeth.” And you’re not totally out of control, but on a population level, it’s getting enough people sucked into that having more than you really should, that it really has significant health consequences and mental health consequences.

Jared Wadley:

You had touched on the, there’s no studies or there hasn’t been any focus on brain activity. Is that something that’s going to be seen in research down the road?

Ashley Gearhard:

Yeah. So actually the good news is there’s tons of brain research. We actually do some of it here in my lab here at Michigan. We’ve done things like look at people’s brains while they watch fast food commercials and then we bring them into… I have a little simulated fast food restaurant lab and we see how their brain response predicts what they’re going to eat. And we’ve done similar things where right now we’re giving people a chocolate milkshake while we scan their brain.

And there is strong brain evidence that all addictive substances seem to activate the mesolimbic dopamine center of the brain. This is the brain that makes you crave and feel motivated and to see that cue and suddenly want it. All addictive agents seem to really converge on that system. The problem is lots of things converge on that dopamine system. When you drink water, when you listen to music, when you hug a loved one, addictive substances and behaviors are acting on the reward and motivation system that evolved to make sure that we took care of ourselves and we did things that were good for us.

The problem is with enough industrial engineering, suddenly that reward and motivation system instead starts driving people to consume things that aren’t good for them and they really struggle to get control of it even if they really want to.

But we don’t… It’s not as simple as being able to put somebody in a brain scanner and give them something and say, “Oh, we had 200% dopamine. That’s addictive.” Because it’s very hard to measure and it’s very sensitive to how much food you’ve eaten that day, what your genes are. So we really have been able to resolve these controversies about whether prescription opioids were addictive, whether gambling was addictive. Our real gold standard has been, is it triggering that cascade of behavioral and psychological experiences of that loss of control and cravings?

So the brain is really an important part of it, but it isn’t the black and white. You just go gold standard, we scan the brain, now we know it’s addictive, debate over. I wish it was that easy, but it’s not.

Jared Wadley:

Yeah. And building on that, are there certain ingredients or characteristics of highly processed foods that make them likely to drive over-consumption?

Ashley Gearhard:

Yeah. So the thing that’s really interesting is that we see if you get food from mother nature, food that it’s pretty close to its natural form, it really has a certain signature. You see products that will be a source of carbohydrate, let’s say, a sugar or a starch, but they’re almost always, like if you think of berries, like a strawberry, it’s going to give you a rush of sugar, but it’s in this delivery package where there’s lots of water, there’s these vitamins, there’s fiber. You can’t mainline a bunch of strawberries into your stomach and into your mouth. They also aren’t very densely packed. That sugars really diffuse in the water and the fiber. And you often in nature do not get carbohydrates and fats in the same food.

We see that our reward system pays a lot of attention to when you’re getting carbohydrates and fats because they’re energy-rich and that’s great. That’s why we like nuts and meats and strawberries and bananas and why we’ve been able to get enough energy to survive an environment that’s generally been really scarce with calories. If you didn’t care about that stuff, you’re not going to survive.

But the problem is that now with the processing, the delivery mechanism for those carbs and those fats is now mostly these ultra processed foods. And by that, this is a food that when you look at the ingredients, many of them, you don’t know what the heck they are, you can’t name them, you couldn’t make it in your own kitchen. Many of those products are delivering these unnaturally intense and concentrated combos of rapidly absorbable carbohydrates and added fats. That combination just does not exist in nature and our brain never evolved to handle that amount of intense reward stimulation in a food.

But it doesn’t just stop there. The industry is really able to take a lot of strategies and do things where they can enhance the sensory profile through very intense chemistry where you can get flavors that tell you, “Ooh, this is like a strawberry,” but actually there’s no strawberry in it. Like I always love Fruit Loops. There’s no fruit in Fruit Loops. So many of these products give you the signal of a food that exists in nature that your brain was wired to care about, but it’s chemically engineered IN a factory.

And when you get that, that really intense sensory flavors combined with this really intense hit of refined carbs, often refined carbs and fats, it really wakes the brain up in a way where you start to crave that sensory profile. You want the taste of the Coca-Cola, you want the burn of the flaming hot Cheeto, you want the strawberry of the strawberry milkshake that might not have any strawberries in it. And so you seek that out and you crave that.

Jared Wadley:

And there’s a growing national conversation about food policy. What are your thoughts on Health and Human Services Secretary Robert F. Kennedy Jr’s Make America Healthy Again movement, particularly when it comes to targeting certain food ingredients?

Ashley Gearhard:

Yeah. So I think they are tapping into a real desire in this country that I think goes across political lines. Again, I’m a mom and I find when I go to the grocery store, like the amount of ultra-processed food that is flooding the shelves, and most of it is health washed, there’s a health claim. I mean, I just drove by Dunking Donuts and it was protein, protein, protein. It’s confusing for consumers out there.

I think any political party that doesn’t really hear how sick Americans are of feeling like corporate profits are being put ahead of us and our children thriving and living healthy lives is going to miss the boat. And I would encourage all of our political and kind of advocacy and regulators to really attend to that. We have polling that if there’s one thing Americans can agree on is that the food industry, that the food supply and the food industry don’t have their best interest at heart right now.

And so it’s encouraging to see movement in this area. I think that a lot of us really attend to the fact that if we don’t call out the role of the industry and the way they’re flooding the environment and making it really hard, especially if you don’t have a lot of money, if you are really scraping to get enough food every month, what’s cheap, accessible, affordable, and heavily marketed to you, I would argue isn’t even real food in many cases. So I’m really hoping to see upstream policies that help change the default of where Americans get their calories.

Jared Wadley:

And you were one of 43 global experts who recently authored a three paper series on ultra-processed foods. The research argued that the problem isn’t just an invisible choice, but a broader system shaped on corporate interest rather than nutrition and sustainability. Can you give us like one or two of the key findings in how the United States compares to other countries?

Ashley Gearhard:

Yeah. So the United States, we’re such an outlier. We’re so bad. We’re totally the worst of the worst when it comes to how much of our food supply is ultra-processed. The current estimate, that it’s about 67 to 70% of our food supply is ultra-processed. We see that we are most certainly the most metabolically ill country of any country in the world. And when you track how that has gone up over time, it tracks with the transition of our food supply to being more ultra processed.

One thing a lot of people don’t know is in the 1970s and ’80s, Philip Morris and R.J. Reynolds, the big tobacco companies, actually bought up many of the major processed food and beverage companies like Kraft and General Foods. They created products like Hawaiian Punch and Fig Newtons and Lunchables. They divested when the heat started coming in the 2000s with the obesity epidemic.

But the science really finds, especially in America, that the know how of the tobacco industry in shaping our food supply has just changed the DNA of the food that we have available to us and grocery stores and corner stores and all of that. And where I see that we are also probably an outlier in what we’ve done about it. I mean, many other countries are really taking this on in force. Chile is a big one that puts big warning labels on these products on the front, these huge octagon stop signs that really help you make an informed choice as a consumer about it. The UK just passed a big law about you can’t market these unhealthy products anytime before 11:00 PM to reduce exposure to children, to constantly getting these messages.

I think there’s so much we could do. We also see in America that the ultra-processed food and beverage company spends more money lobbying than tobacco, alcohol or gambling. So there’s a big reason I think on the power structure of why we haven’t seen the change that people really want and need. I really hope that’s changing and I really see the motivation that people have for wanting a better future for our kids.

Jared Wadley:

Before we wrap up, let’s bring it back home to the University of Michigan. Can you tell us about the Food and Addiction Science and Treatment Lab, also known as FAST Lab, located here on campus? When did it open and what have you learned so far from its operations?

Ashley Gearhard:

I feel so supported by Michigan in building me this lab. When I first got here, they asked me, “What are you thinking for a lab?” And I sent them a picture of a fast food restaurant and I said, “I want to build a simulated fast food restaurant where it looks like you’re walking into a fast food restaurant. We can make our own french fries and strawberry milkshakes and cheeseburgers.” And Michigan said, “Okay.”

And scientifically, that’s really important. Again, I trained in alcohol and we had simulated bar labs and so it looked like you were in a bar in the basement of the psych department. And so I saw firsthand how powerful it was to be in that cued context space to really be able to make our research translate to the real world.

And so we’ve seen in the FAST Lab that we can… I think it’s helpful to have the science, but we all inherently know this, that when people are given a menu of food options and they’re in a normal space, kind of office space, they can make healthier choices.

Once we get them into our cued french fry smelling, simulated fast food restaurant, people overwhelmingly choose the ultra-processed french fries and cheeseburgers. They eat about 400 more calories than in other environments. And it’s driven really by that craving that the food doesn’t taste any better in our fast food restaurant, according to our participants. But when they walk in and they see all those cues, it gets that dopamine system going and it makes you crave.

And it’s part of why, what we’ve learned about why our modern food environment can be so tricky is those cues and those triggers are now everywhere. And so I think we have a really nice scientific way to understand how those cues kind of get in under the skin and really set you up despite your best intentions to not get the salad, but instead get the cheeseburger, french fry, strawberry milkshake meal.

Jared Wadley:

And then in the lab, you’re working with students.

Ashley Gearhard:

Yeah.

Jared Wadley:

How’s that gone so far?

Ashley Gearhard:

It’s so good. My students are so smart. They’re such team players. We actually, as part of really wanting to set that environment, have our undergrads dress up as fast food restaurant workers with the apron and the little hat and they make french fries. I always walk down and I’m like, “Smells like french fries. We must be getting data.”

And so the University of Michigan undergrads and our doctoral students are just fundamental in really making the science work and allowing us to really peel back the layers of understanding why it’s so hard to make healthy choices in the modern world that we’re living in, so we can develop tools, strategies and policy suggestions so people can really live healthy and happy lives for themselves and the next generation as well.

Jared Wadley:

Yeah. It sounds like a cool operation and definitely let me know when I can be a tester there.

Ashley Gearhard:

Absolutely.

Jared Wadley:

Ashley, thank you so much for joining us today and sharing about your research.

Ashley Gearhard:

Thank you. I really appreciate it. Thank you for talking to me about it.

Jared Wadley:

Thank you for listening to this episode of Michigan Minds, which is produced by Michigan News, a division of the office of the Vice President for Communications.