Subscribe
Share
Share
Embed
Truth Seekers: Where Data Meets Reality
Tired of sensational headlines and conflicting health advice? Join Alex Barrett and Bill Morrison as they cut through the noise to uncover what scientific research actually says about the claims flooding your social media feed.
Each week, Alex and Bill tackle a different health, nutrition, or wellness claim that everyone's talking about. From "blue light ruins your sleep" to "seed oils are toxic," they dig into the actual studies, examine the methodologies, and translate the data into plain English.
No agenda. No sponsors to please. No credentials to fake. Just two people committed to finding out what's really true by going straight to the source—the research itself.
Perfect for anyone who's skeptical of influencer health advice but doesn't have time to read every scientific study themselves. New episodes drop regularly, delivering clarity in a world full of clickbait.
Question everything. Verify with data. Find the truth.
Disclaimer: Truth Seekers provides educational content based on published research. Nothing in this podcast should be considered medical, financial, or professional advice. Always consult qualified professionals for decisions affecting your health and wellbeing.
**The 62% Brain Decline Myth: What That Artificial Sweetener Study Actually Shows**
Alex: Right, so I need to talk about this headline that's been absolutely everywhere: "Artificial Sweeteners Linked to 62% Faster Cognitive Decline." And honestly, when I first saw it, I thought, well, that's it then, isn't it? My morning Diet Coke is rotting my brain.
Bill: Yeah, I saw that one too. The 62% number is doing a lot of heavy lifting in those headlines.
Alex: Exactly. And everyone I know was talking about it. People sending it to their family WhatsApp groups, that kind of thing. Because pretty much everyone knows someone who drinks diet soda or uses artificial sweeteners. It feels personal.
Bill: So this study came out in Neurology in 2025. Decent journal. And it followed over 12,000 Brazilian civil servants for eight years, looking at artificial sweetener consumption and cognitive decline. That's actually a pretty solid sample size and time frame for this kind of research.
Alex: Hang on though, because I remember seeing headlines that made it sound like they'd proven artificial sweeteners cause brain damage. But when I actually looked at the study...
Bill: Right, so here's where we need to pump the brakes. This is an observational study, not a randomized controlled trial. They watched what people ate and what happened to their brains over time. They measured associations, not causation.
Alex: Which means they can tell us that these two things happen together, but not that one causes the other.
Bill: Exactly. And this distinction matters so much here because of what they actually found. So they measured consumption of seven different low-calorie sweeteners at baseline—that's 2008 to 2010—and then tracked cognitive performance over eight years using standardized tests.
Alex: And they found that people in the highest consumption group showed faster cognitive decline. That's where the 62% comes from, yeah?
Bill: That's where it comes from, but let me explain what that number actually means. Because this is one of the most misleading statistics I've seen in health headlines this year.
Alex: Go on then, I'm bracing myself.
Bill: Okay, so the 62% is a relative risk ratio. They compared the group with the highest sweetener consumption to the group with the lowest consumption and found that the high-consumption group's decline was 62% steeper. It's a ratio comparing two rates of decline.
Alex: But that's not the same as saying my brain is aging 62% faster than it should be normally.
Bill: Not even close. The actual effect sizes—the beta coefficients they measured—were negative 0.024 for global cognition and negative 0.040 for verbal fluency. These are tiny numbers on a standardized test scale.
Alex: Right, so in actual human terms, what does that mean?
Bill: It means the difference in test scores between the highest and lowest consumption groups was incredibly small. Less than half a standard deviation. You probably wouldn't even notice it in day-to-day life.
Alex: Okay, but wait—I need to push back on something here. You're saying the effect is tiny, but they tracked twelve thousand people for eight years. That's a massive study. If they're finding an effect at all with that kind of sample size, doesn't that suggest there's actually something real going on?
Bill: That's... actually a fair point. A big sample size does give you more statistical power to detect real effects.
Alex: Right, so maybe the effect is small, but it's real. Maybe we shouldn't be dismissing it just because the number looks small to you.
Bill: Okay, but here's the thing—statistical significance doesn't equal practical significance. Yes, they had enough people to detect a tiny difference. But tiny differences can also be artifacts of confounding. And that's where this study starts to fall apart for me.
Alex: What do you mean?
Bill: So here's what I find interesting—they only found these associations in people under 60. People 60 and older? No effect at all.
Alex: Huh.
Bill: Right? And if artificial sweeteners were directly causing cognitive decline through some biological mechanism, why would age matter? The inconsistency suggests something else is going on.
Alex: Like what though?
Bill: So here's where reverse causality becomes the likely explanation. Think about who uses artificial sweeteners. It's disproportionately people with metabolic problems—diabetes, pre-diabetes, obesity. People who are trying to manage their weight or blood sugar.
Alex: Oh, so you're saying the artificial sweeteners aren't causing the decline. The underlying health problems are causing both the sweetener use and the cognitive decline.
Bill: Exactly. And the study actually supports this interpretation. They found stronger associations in participants with diabetes. If the sweeteners themselves were the problem, why would it be worse in diabetics? But if metabolic disease is the real culprit, that's exactly what you'd expect.
Alex: Wait, hang on. Didn't we do something about sweeteners before? I feel like we've talked about this exact thing.
Bill: The weight loss one?
Alex: Yes! The diet soda episode. Where we talked about how people who are already overweight switch to diet products, and then studies make it look like the diet soda caused the weight gain.
Bill: Oh yeah, same problem. Classic reverse causality.
Alex: Right, okay. So we're seeing it again here. That actually makes me feel better about your interpretation—it's not just you theorizing, we've seen this pattern before with sweeteners.
Bill: Yeah, and here's another issue—they only measured diet at baseline. So in 2008 to 2010, they asked people what they ate, and then they followed them for eight years. But people's eating habits change over eight years.
Alex: Right, and they're assuming that whatever you reported eating in 2008 is what you kept eating for the next eight years.
Bill: Which we know isn't true. And on top of that, all dietary data was self-reported. People are notoriously bad at accurately reporting what they eat.
Alex: I can't even remember what I had for lunch yesterday, let alone quantify my artificial sweetener intake.
Bill: And check this out—the measured intake levels were absurdly low. They found people consuming like 3 milligrams per day of xylitol and 0.1 milligrams per day of erythritol. But a single stick of sugar-free gum contains grams of these compounds. Not milligrams. Grams.
Alex: Wait, did you say milligrams?
Bill: Milligrams.
Alex: So the actual exposure levels they measured were... way below what people actually consume in real life?
Bill: Way below. Which raises questions about measurement error. Were people underreporting? Were they actually consuming these sweeteners in amounts too small to matter biologically? I don't know.
Alex: And meanwhile, the headlines are telling everyone that artificial sweeteners are destroying their brains.
Bill: Here's what really frustrates me about this—the study authors themselves acknowledged these limitations. In their paper, they literally wrote: "Study limitations include self-reported dietary data, selection bias from attrition, and residual confounding from co-occurring health behaviors."
Alex: They knew this wasn't definitive evidence.
Bill: They called it "preliminary and hypothesis-generating." Which in science speak means, "We found something interesting that needs way more research before we can say anything conclusive."
Alex: But that's not what made it into the headlines, is it? What made it into the headlines was "62% faster cognitive decline" and "equivalent to 1.6 years of brain aging."
Bill: That 1.6 years number is particularly egregious because it's an extrapolation. They took those tiny beta coefficients and calculated what it might theoretically mean in terms of aging. It's not a measured finding.
Alex: So we've got small effect sizes, observational data that can't prove causation, reverse causality that hasn't been ruled out, inconsistent findings by age group, and measurement problems. And none of that context made it into the coverage.
Bill: And other researchers called this out. The journal published responses from experts pointing out these exact issues. One group from the University of Basel noted that the measured polyol intakes were "far below real-world exposures" and said the associations "may simply reflect residual confounding."
Alex: Which brings me to what I'm actually wondering about—what should people do with this information? Because I guarantee there are people who read those headlines and immediately switched back to regular soda.
Bill: Which would be ironic because we have really solid evidence that regular sugar consumption is associated with metabolic problems, weight gain, diabetes—all things that are actually bad for your brain.
Alex: So the headline might have pushed people toward a choice that's actually worse for their health.
Bill: That's the real harm here. Not the study itself—the study is fine for what it is, which is preliminary observational research. The harm is in the translation from "we found a small association that might reflect reverse causality" to "artificial sweeteners are destroying your brain."
Alex: What would you need to see to actually be convinced there's a causal relationship here?
Bill: A randomized controlled trial. Take people, randomly assign them to consume specific doses of artificial sweeteners versus placebo, control for diet quality and metabolic health, and measure cognitive outcomes. That's how you establish causation.
Alex: And we don't have that.
Bill: We don't have that. What we have is an interesting association in observational data that raises questions worth investigating further. That's it.
Alex: Right, so here's what listeners should actually take away from this. The study found that people who consume more artificial sweeteners show slightly more cognitive decline, but it's a small effect, it only showed up in people under 60, and it's very likely explained by reverse causality—meaning the underlying health conditions drove both the sweetener use and the decline.
Bill: If you're using artificial sweeteners as a tool to avoid regular sugar because you're managing diabetes or trying to lose weight, this study doesn't give you a good reason to stop. The benefits of avoiding sugar probably still outweigh any theoretical risk.
Alex: And if you're not a regular diet soda drinker, don't start because you think it's a health miracle. But also don't panic if you have one occasionally.
Bill: The boring truth is: whole foods are still better than processed foods with or without artificial sweeteners. But between diet soda and regular soda, diet is probably still the better choice for most people.
Alex: And the broader lesson here is about how we read health headlines. When you see a percentage like 62%, ask yourself: 62% of what? Is that relative or absolute risk? What's the baseline?
Bill: And always, always look for whether it's observational or experimental. Association or causation. Those distinctions matter.
Alex: Because the truth is almost always more complicated than the headline. And that's not... I mean, it's not entirely the media's fault. When I was covering health stories, complicated doesn't get clicks. Complicated doesn't get shared. But it is our job to figure out what the actual evidence says.
Bill: And in this case, the actual evidence says: interesting association, needs more research, don't panic, and definitely don't switch back to regular soda based on this alone.
Alex: Brilliant. I'm keeping my morning Diet Coke then.
Bill: Just maybe eat some actual food with it.
Alex: Fair enough.