Explosive diarrhea, ‘protein maxxing’ and the science of burnout

Summary

Science Quickly Podcast Episode Summary

Episode Title: Explosive diarrhea, ‘protein maxxing’ and the science of burnout
Date: August 3, 2026
Host: Rachel Feltman (Scientific American)
Guests: Adam Kovach (Breaking News Reporter), Andrea Garleski (Chief Newsletter Editor)

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Episode Overview

This episode explores recent scientific developments in public health, nutrition, climate science, and neuroscience. Host Rachel Feltman leads a tight, accessible roundup: a nationwide outbreak of foodborne illness, the myths of high-protein dieting, Europe’s record-breaking wildfires, and the neuroscience of mental exhaustion. The tone is informative and upbeat, with moments of levity.

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Key Discussion Points & Insights

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1. Outbreak of Cyclospora (‘Explosive Diarrhea Parasite’)

[01:03 – 04:43]

Highlights

• Cyclospora (Cyclospiriasis): A surge in cases of this foodborne parasite, mainly in Michigan (over 10,000 cases and 193 hospitalizations as of July 30), with the CDC tying outbreaks to iceberg lettuce from Taylor Farms de Mexico.
• National Spread: Eight other states have reported increases; possibility of more undetected/untied cases.
• Second Outbreak: An unrelated spike centered in North Carolina (718 cases since May), with parsley and cilantro frequently—but not consistently—implicated.
• Expert Quote:
  “For now, the best way to lower your risk is, unfortunately, if you love salads, not to eat salads, you should cook all your produce if you can.” — Rachel Feltman [03:55]
• Prevention Advice:
  • Cook produce when possible.
  • Wash all fruits and vegetables thoroughly.
  • Always wash hands after handling raw produce.

Tone & Memorable Moment

• Feltman interweaves serious public health news with dry humor regarding the “exploding diarrhea parasite” and the tragedy for salad lovers.

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2. The Science of ‘Protein Maxxing’ and Longevity

[04:43 – 07:38]

Guest Segment: Adam Kovach (Breaking News Reporter)

Key Points

• Research Overview:
  Recent review studies—mostly in animal models—suggest high-protein diets could negatively impact lifespan.
• Mechanism:
  • Protein restriction boosts FGF21 hormone, leading to more mitochondria in fat tissue and better metabolic health.
  • Excess protein digestion increases urea, risking kidney damage.
  • High-protein diets often include more saturated fats, which harm cardiovascular health.
• Striking Data Point:
  • Brook trout on restricted protein diets live 128% longer (animal models—not human data).
• Mythbusting:
  “There's only so much protein that your body can metabolize, and so a lot of excess protein just ends up either getting stored as fat or burnt off for energy. So you really don't need to overdo it with protein.” — Adam Kovach [06:22]
• Practical Takeaway:
  Moderation is key; no need for “protein-infused water” or extreme supplementation.

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3. Historic European Wildfires and Pyrocumulonimbus Formation

[07:38 – 09:18]

Host Discussion

Details

• Record Wildfire Years:
  • 2025: Worst wildfire year on record in Europe (over 1M hectares burned).
  • 2026: On track to surpass that, with Spain & France hit hardest.
  • France experienced its first-ever pyrocumulonimbus event (fire-generated thundercloud producing lightning and more fires).
• Climate Connection:
  Blazes fueled by repeated heatwaves and contribute to evacuation of hundreds of thousands.
• Memorable Description:
  “…smoke monsters can produce lightning, which often creates even more fire when it strikes the hot, dry ground.” — Rachel Feltman [08:34]

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4. Neuroscience of Burnout: Mental Exhaustion and Decision-Making

[09:18 – 11:29]

Guest Segment: Andrea Garleski (Chief Newsletter Editor)

Study Insights

• FMRI Study:
  Monitored brain activity in 28 people performing challenging memory tasks.
• Decision Experiment:
  Participants could opt for more difficult tasks for higher rewards, but as they tired, they chose less effortful (less rewarding) options.
• Brain Mechanisms:
  • Interaction between dorsolateral prefrontal cortex and right anterior insula signals rising fatigue.
  • As mental exhaustion grows, motivation for challenging cognitive work drops.
• Evolutionary Rationale:
  These neural signals likely evolved to protect the body from overexertion—though sometimes at the cost of beneficial effort.
• Notable Quote:
  “You may be exhausted, but some tasks are worth pushing through.” — Andrea Garleski [11:22]

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Notable Quotes & Moments

• Salad Safety in the Age of Cyclospora:
  “Unfortunately, if you love salads, not to eat salads, you should cook all your produce if you can.” — Rachel Feltman [03:55]

• Protein Moderation Real Talk:
  “You really don't need to overdo it with protein. If you're really interested in… seeing some gains, everything in moderation tends to be a pretty good rule.” — Adam Kovach [06:42]

• Nature’s Fire-Breathers:
  “…[pyrocumulonimbus] smoke monsters can produce lightning, which often creates even more fire when it strikes the hot, dry ground.” — Rachel Feltman [08:34]

• Burnout and Your Brain:
  “These fatigue signals have likely evolved to protect us from overtaxing our cognitive and physical systems.” — Andrea Garleski [10:41]

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Segment Timestamps

• Cyclospora Outbreak & Food Safety: [01:03 – 04:43]
• Protein Intake and Lifespan Science: [04:43 – 07:38]
• Record Wildfires & Pyrocumulonimbus: [07:38 – 09:18]
• Neuroscience of Burnout: [09:18 – 11:29]

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Conclusion

This lively, information-packed episode offers practical health guidance (cook your veggies!), challenges protein diet fads with up-to-date evidence, delivers sobering climate news, and clarifies the biology behind burnout. Listeners gain both actionable advice and deeper science context, all delivered in the quick, friendly style characteristic of Science Quickly.

Transcript

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[Rachel Feltman]

Happy Monday listeners, and happy August for Scientific American Science. Quickly, I'm Rachel Feltman. We're finally back with another one of our science news roundups. I'll start with a story that pretty much everyone I know has been asking me for science backed advice. Cyclospora, otherwise known as the exploding diarrhea parasite. If you are either living outside of the US or living under a rock, this microscopic parasite has been causing big gastrointestinal issues. This summer, as of July 30, Michigan alone had reported more than 10,000 cases of cyclospirasis, a disease caused by the parasite that can lead to bouts of sudden watery diarrhea, including 193 hospitalizations. That's compared with around 40 or 50 cases in a typical year, according to the state's chief medical executive, Natasha Bagdasarian. And it's likely that many cases have actually gone unreported. Another eight states have also seen an uptick in cases that the Centers for Disease Control and Prevention has tied to the same outbreak. First, the good news. The cases in those nine states have been linked pretty solidly to iceberg lettuce, specifically shredded lettuce sourced from Taylor Farms de Mexico. But it's too soon to tell whether or not other as yet unidentified and unrecalled streams of produce have also been contaminated. So just avoiding iceberg lettuce is good, but probably, probably not sufficient. And that means that while it's reasonable to hope that cases have peaked, public health experts say those states aren't necessarily out of the woods just yet. And now for some more not so great news. There does seem to be a second unrelated outbreak happening as well. Now, we do tend to see spikes in cases of foodborne illness, especially those related to pathogens spread by contaminated feces every summer. So it would be normal to see some number of cyclosporicis cases regardless. And indeed, as of last week, there were several separate instances of cyclospirasis outbreaks with no known cause under active investigation by the Food and Drug Administration. But this second cluster is worth noting because it already includes an unusually high number of cases in North Carolina, where state officials have started actively tracking the outbreak. There have been 718 cases reported since maybe May, most of which have occurred since mid June. Based on surveys, North Carolina health officials say that parsley and cilantro seem to be a common denominator in many cases, but not all. For now, the best way to lower your risk is, unfortunately, if you love salads, not to eat salads, you should cook all your produce if you can. Of course, you should also wash all of your produce before consuming it, regardless of how you're going to prepare it. And you should also remember to wash your hands after handling any raw fruits and veggies. Speaking of eating healthy, which for now may mean saying no to that side salad, we've talked before on the show about the world's current obsession with protein. You can go check out our May 13 episode to hear more about why protein maxing can often be unnecessary. But now new research suggests that easing up on protein could actually have a positive impact on your lifespan. Here to tell us more about that story is Scientific American breaking news reporter Adam Kovach.

[Adam Kovach]

Hi, Rachel. So this new study is actually a review of a lot of the other studies that have come out over the past few years about what we should be eating, how much protein is good for us. And so a lot of this was conducted in animal models like mice, because it's really hard to adjust somebody's protein diet for their entire life. And when they reviewed all of it, they found that eating too much protein could actually have a really negative effect on a person or a mouse's lifespan. So there's a few reasons that protein can affect lifespan, and one of them has to do with when you restrict the amount of protein you take in. It can actually lead to a boost in a production of a hormone called FGF21, mostly in the liver. And so when that hormone reaches your brain, it triggers a process called sympathetic signaling. And that's where the nervous system can cue white adipose tissue or fat to actually generate more mitochondria. And that in turn leads to the fat getting burned as fuel. So what that means is you actually reduce your chances of developing things like heart disease or diabetes or some cancers. And there's other reasons that restricting protein can promote a longer lifespan. One of them is that when protein is digested, the end metabolic product is something called urea. And when you have excess urea, that can actually lead to major kidney problems. But also one of the other reasons that eating too much protein can be bad for you is foods that have a lot of protein also tend to be high in saturated fats. And as I'm sure a lot of our listeners know, eating too much of those is linked to a lot of nasty side effects, like a higher risk of heart disease. Now turning to the results, it really varied by animal. If you look at brook trout, for instance, when they were put on a protein restricted diet, they saw their average lifespan increase by 128%. So keep in mind this is animal models. So it's hard to say how this reflects in human beings, but the results are pretty undeniable. So one thing that I found really interesting is that we often think about eating a lot of protein is connected with like building a lot of muscle. And that's not always the case. There's only so much protein that your body can metabolize, and so a lot of excess protein just ends up either getting stored as fat or burnt off for energy. So you really don't need to overdo it with protein. If you're really interested in, you know, going to the gym and seeing some gains, everything in moderation tends to be a pretty good rule for the future of protein. Maxing, it can be a little bit difficult to figure out what this means. This isn't necessarily new knowledge. This paper really was just summarizing something that scientists in this area have known for quite some time. Hopefully people take this under consideration and realize that they don't need to be buying protein infused water and drinking that to really boost their muscle gains or anything like that. But if you're interested in learning more, you can read about it on scientificamerican.com

[Rachel Feltman]

thanks for that, Adam. Now let's touch briefly on some climate news. 2025 was Europe's worst year of wildfires on record, with more than a million hectares burning throughout the EU as of last week, 2026 was actually on track to beat that record, thanks to grossly atypical activity in France and Spain. According to reporting by CNN. As of July 29, Spain had seen nearly double its usual wildfires for an entire year, while France had nearly three and a half times as many as average. Fires in France and Spain over the last few weeks have spurred hundreds of thousands of evacuations. One blaze in southwest France grew powerful enough to create its own weather in a phenomenon known as a pyrocumulonimbus. This is when a fire emits enough smoke to seed a cloud, with water vapor condensing around ash particles. Just like a cloud in a regular thunderstorm, these smoke monsters can produce lightning, which often creates even more fire when it strikes the hot, dry ground. The AP reports that according to French officials, this was the first pyrocumulonimbus ever recorded in the country. Repeated heat waves are driving these unprecedented wildfires and contributing to blazes in other parts of Europe as well. This seems like as good a time as any to talk about the concept of mental exhaustion. We all know what cognitive fatigue feels like, but how does it actually impact the choices we make? A team of neuroscientists recently tried to find out by watching how mental exhaustion changes brain activity. Here to tell us more about that story is Andrea Garleski, chief newsletter editor at Scientific American.

[Andrea Garleski]

Thanks, Rachel. Yeah, I think this is one most people will be able to relate to. It turns out that mental exhaustion affects her decision making. No surprises there, but scientists pinpointed the region in the brain that seems to be controlling this phenomenon. In a recent experiment, researchers used a functional magnetic resonance imaging machine, an FMRI, to monitor the brain activity in 28 people while they are performing certain cognitive tests. Like they asked them to recall strings of letters with varying degrees of difficulty. So after a while of wearing these people out with these tests while they're in the brain scanner, the researchers asked them each an interesting question. Would they like to keep going for money? Either a dollar for correctly completing an easy memory test or up to $8 for correctly answering a harder memory test. What the scientists found was that as participants became more cognitively fatigued, they were much less likely to choose the more demanding option, even though they could get paid more for it. So what region of the brain was lighting up during all this testing? As people completed ever more exhausting memory tasks, an area at the front of the brain called the dorsolateral prefrontal cortex sent out increasingly strong signals to the right anterior insula, a region toward the middle right of the brain that is known for monitoring how the body is feeling, including levels of fatigue. As they saw, cognitive fatigue significantly decreased people's motivation to engage in challenging tasks. The more their brain worked, the more signals traveled between these two brain regions. Based on these patterns, the researchers were able to compute a person's willingness to trade cognitive effort more tests for reward money. These fatigue signals have likely evolved to protect us from overtaxing our cognitive and physical systems, the scientists say. The problem is sometimes mental exhaustion can prevent us from completing tasks that restore our internal energy, like going outside for a walk or cooking a healthy meal instead of getting greasy takeout. You may be exhausted, but some tasks are worth pushing through if you want to get fascinating updates like these five days a week. Subscribe subscribe to my free daily newsletter Today in [e-mail] Newsletter Thanks Andrea listeners.

[Rachel Feltman]

Don't forget to subscribe to Today in Science to get more SIAM stories like that one sent straight to your inbox. That's all for today's episode. Tune in on Wednesday for a special chat with the Internet's favorite inventor, Simone Giertz herself. Science Quickly is produced by me, Rachel Feltman, along with Fonda Mwangi and Jeff d'. Alvisio. This episode was edited by Alex Seguiera, Marielle Issa and Erin Shattuck. Fact check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up to date and in depth science news For Scientific American, this is Rachel Feltman. Have a great week. Close your eyes, exhale, feel your body relax and let go of whatever you're carrying today. Well, I'm letting go of the worry that I wouldn't get my new contacts

[Andrea Garleski]

in time for this class.

[Rachel Feltman]

I got them delivered free from 1-800-contacts. Oh my gosh, they're so fast. And breathe. Oh, sorry. I almost couldn't breathe when I saw the discount they gave me on my first order.

[Andrea Garleski]

Oh, sorry.

[Rachel Feltman]

Namaste.

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