This is a transcript of the Gastropod episode, The Keto Paradox: Fad Diet *and* Life-Saving Medical Treatment, first released on August 22, 2023. It is provided as a courtesy and may contain errors.

VOICEOVER: Here is a diet that goes against all conventional nutrition advice. Banning bread, potatoes and pasta in favor of red meat, eggs and bacon. What’s not to love?

WOMAN: People all of a sudden are allowed to eat cheese. And all of a sudden they can have a steak a few times a week they couldn’t have before. They can eat the eggs with the yolk.

JOE ROGAN: Most, most of my diet is just meat. Wild game meat. Ribeye steaks.

CYNTHIA GRABER: This is something I’ve heard on and off for literally decades, people saying that they are cutting out all sorts of things that I love, like grains and beans and bread and most fruit and even a bunch of vegetables in favor of steak and bacon. And that this is a good thing.

NICOLA TWILLEY: Me too, and I hate hearing it. For a lot of reasons, some of which are to do with the concept of diets in general, which we talked about in our episode on diets and dieting, and some of which are to do with the fact that eating basically only meat and fat sounds terrible.

GRABER: And frankly, like kind of a disaster for the environment. But one of our listeners made us think about this topic in a new way:

KATHRYN ELKINS: Hi, Gastropod. This is Catherine Elkins from St. Louis, and I just listened to your recent podcast on medically tailored meals, and it got me thinking about a dietary therapy that we use in patients with epilepsy called the ketogenic diet.

TWILLEY: Kathryn is not only a Gastropod listener, she’s also a pediatric neurologist.

ELKINS: I treat children with epilepsy. And that includes both treatment with medicine and both non-medicine options. So of course I use a lot of different epilepsy medications, which of course have all of their side effects and whatnot. But other non medicine options do include surgery. And then my favorite type of treatment is the ketogenic diet.

TWILLEY: This was news to me. Something I’d dismissed as celebrity nonsense turned out to be a genuine medical treatment. We were intrigued.

GRABER: And, since we are Gastropod, be careful about intrigue, because side effects may include making an episode. Yes, you are listening to Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber.

TWILLEY: And I’m Nicola Twilley. And this episode, we are exploring the history and science of keto. What actually are ketones, and what on earth is going on in our bodies when we’re in ketosis?

GRABER: Most of the people in the US who are following the keto diet do not have epilepsy, so why are they doing it? Does it do what they think it does?

TWILLEY: And who came up with this plan in the first place? All that this episode plus some Jane Fonda.

GRABER: This episode is supported in part by the Burroughs Wellcome Fund for our coverage of biomedical research and by the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology and Economics. Gastropod is part of the Vox Media Podcast Network, in partnership with Eater.

[MUSIC]

TWILLEY: First of all, this word keto. What exactly is keto when it’s at home?

ADRIENNE BITAR: Well, the, the keto diet is low-carb dieting. It’s very low-carb dieting. The theory goes that you’re burning your fat stores for energy rather than relying on carbohydrate storage.

GRABER: Adrienne Bitar is a lecturer in American Studies at Cornell University, and she’s the author of the book Diet and the Disease of Civilization. So now we know that keto is a diet that’s low in carbohydrates, but why call it keto?

EASTER: The idea is that it puts you into a state called ketosis, where your body is basically running on these molecules called ketones.

TWILLEY: That’s Michael Easter, he’s a lecturer at the University of Nevada Las Vegas and he writes about health and wellness. And I have to say, this is beginning to sound like one of those circular arguments where keto is when you have ketones and ketones are what you get when you do keto. But maybe that’s because I don’t have a clue what ketones are. So what are they?

GRABER: Shivam Joshi is a doctor and a professor of medicine at NYU. and he told us they’re a chemical that’s created when our bodies break down fat.

SHIVAM JOSHI: And they can also be used as energy by certain organs within the body. And so this is why the ketogenic diet gets its name.

TWILLEY: Our bodies break down fat and produce ketones when they don’t have access to their number one most preferred source of energy.

JOSHI: So the body normally fuels itself from carbohydrates. The body takes these carbohydrates, breaks them down, and then uses them for energy. And that ultimately is used for energy, and that’s the body’s preferred source of energy.

GRABER: There are lots of reasons the body might not have access to carbs and might have to burn some fat and make ketones to fuel itself instead. We naturally go into a bit of ketosis when we sleep, and if we fast, or if for some reason we’re literally starving. Biologically, that’s what our fat stores are there for.

TANYA MCDONALD: It’s fairly seamless that our body is sort of well-designed to utilize whichever fuel sources it can get, to power life and, and to keep functioning.

TWILLEY: Tanya McDonald is a neurology professor at Johns Hopkins. And she says it makes evolutionary sense that your body can go into ketosis naturally if it has to. But say for whatever reason you wanted to force yourself into ketosis? Starving yourself is not the only option. You can also eat a ketogenic diet. And what is that?

EASTER: So of, as a percentage of your calories across the day, 90% of your calories that you eat, or rather, an easier way to put that is 90% of the food you eat, has to be from fat. Roughly 4% is carbohydrates and 6% is protein. That’s like the standard ketogenic diet.

GRABER: So Nicky and I both have perhaps unusual memories in that we almost always remember what we’ve been eating. What we ate yesterday, what we ate last week, maybe even last year. We love food, we love to think about it. But that doesn’t mean either of us has any idea what percent of any meal is carbs or protein or fat. So what would a diet like this be like?

EASTER: Practically this means that people would say, wake up and for breakfast they might have an egg with the yolks. We’re not messing with the whites here. And we’re going to cook ’em in butter and we’re going to maybe put some olive oil on ’em and we’ll maybe have like a little bit of spinach with that. And you might have coffee that has butter in it. For lunch, maybe a salad. But granted, you got to go easy on the carrots because carrots are heavy in carbohydrates. Comparatively, right? So you need to be very picky with the vegetables you eat and then, you know, people might have salmon, because that’s a pretty fatty fish. Has protein, but also a lot of fat. Dinner, standard issue dinner for people on keto would be like a really fatty cut of steak, I don’t know my steak cuts. Topped in butter, maybe some more spinach. So it’s a lot of, it’s a lot of fat. It’s very… it’s greasy. It’s a greasy diet. Among diets, I would say it’s the king of grease.

TWILLEY: Yum. And curiously enough eating this kind of way, all this grease—it’s often done with the intention of losing weight. That’s why the very first person to publicly follow and write about this way of eating—cutting out carbs in favor of protein and fat—he was called William Banting, and that’s why he did it.

BITAR: William Banting, 1863. He pioneered the low-carb diet. That included some of the benchmarks of low-carb dieting that we see in the 1970s to today, which is a lot of meat, a lot of fat just low-carb vegetables. Few fruits.

GRABER: We talked about Banting on our history of diets episode, he was a British undertaker who was quite obese, he had a hard time even tying his own shoes, and he had apparently started to go deaf because of the fat deposits in his ears. And he tried and failed to lose weight. Until his ear doctor told him to cut out carbs.

TWILLEY: Which Banting did. In the pamphlet he later wrote about his diet, he said that he had beef, mutton, kidneys and bacon for breakfast, fish and more meat for lunch, and poultry and game, yes more meat, for dinner. And he not only regained his hearing, he also lost lots of weight.

GRABER: That pamphlet was called “A Letter On Corpulence,” and tens of thousands of people read it. But doctors and scientists at the time weren’t convinced.

TWILLEY: Especially because in the late 1800s, the hot new science of food and weight was the calorie. We’ve made an episode about that too. But although the experts were all about calories, it took some time—and another book—to filter down to the public consciousness.

BITAR: The most important figure here is Dr. Lulu Hunt Peters, who in 1918, wrote Diet and Health: With Key to the Calories. And she just pushed this calorie message that we saw coming again and again, not only from popular dieters, but also from later on from the federal government, from nutrition policy research, from the medical field, and so on.

GRABER: And so begins a kind of battle in the public domain. Cut out the carbs! No, it’s calories! No, cut out bread and potatoes!

BITAR: The pendulum swings, right? It goes carbs, cals, carbs, cals, carbs, cals.

TWILLEY: And of course, once you have a mainstream point of view, you always have to have the doubters, the rebels, the ones who dare question. So when the government was pushing cals, the carb haters were the outsiders.

BITAR: So the people who were rebelling against Lulu Hunt Peters already had that sort of renegade aspect in the 1920s. And, and some of those people were like Bernarr McFadden, who changed his name to sound more, more virile.

GRABER: He started life as just ordinary Bernard, but he swapped that boring D at the end for an extra R.

BITAR: So he is Bernarr, like a lion roaring.

MAN: [SINGING] I leap out of bed at the crack of dawn, As graceful as an elk, as nimble as a fawn. The life I lead would gladden, the heart of Bernarr McFadden!

GRABER: Yes Bernarr was famous enough to make it into a song from Gentlemen Prefer Blondes. Bernarr as an adult was a multi- multi-millionaire but he actually grew up poor and was pretty skinny and kind of sickly as a kid. So he got into lifting weights, and then when he was in his twenties he became a pro wrestler. He started writing pamphlets on exercise and fitness and then launched a magazine and wrote books with names like Foot Troubles, the Natural Cure for Rupture, and The Virile Powers of Supreme Manhood.

TWILLEY: Heck yeah. But all of that is a distraction for us, we care nothing for the virile powers of supreme manhood, we are here for Bernarr’s diet advice.

BITAR: He was arguing for intermittent fasting, which some keto dieters do today as well. Well, they’ll eat a lot of fat and proteins over a short period of time and then fast. He also argued for sometimes a liquid diet like the milk diet.

GRABER: Sounds like keto to us. Adrienne says that Bernarr and the people who followed him, even though his diet advice was really well known at the time, his people really felt like they were outside the mainstream, they were fighting the man.

BITAR: And I think that gave what Atkins later picked up on, the sort of rebellious or sort of maverick—kind of off the beaten path atmosphere or personality of these diet gurus who rejected this sort of, persnickety, fussy calories in, calories out. But instead says you, you know, you don’t need to count calories. All you have to do is count carbohydrates. And if you just eat animal products, you don’t even need to do that. You can just eat, and eat, and eat, and luxuriate in these like high class foods like cream and martinis and animal fats, and you’ll, you’ll lose weight magically. And that’s really what gave it to that countercultural edge.

TWILLEY: Countercultural high class decadence sounds like a winning formula. And it certainly was for Atkins, of Atkins diet revolution fame.

BITAR: Robert Atkins was—I would argue, was the most influential diet leader in American history.

GRABER: Atkins was a cardiologist who saw patients in a private practice, and he was overweight. He wanted to lose that weight, and he read an article about low-carb diets and decided to give the whole thing a try.

VOICEOVER: The low-carbohydrate approach to dieting had been kicking around the medical world for over 100 years, but it took Atkins to make it a hit.

TWILLEY: This by the way is from a terrible documentary about Atkins on the Biography Channel.

VOICEOVER: He began putting more patients on a low-carb regimen, and when the high fashion magazine Vogue published an article about it, socialites began beating a well-heeled path to his door.

WOMAN: He was, of course, the diet doctor to the chic and well known at that time. And everybody was flocking to his office.

WOMAN 2: Because the word spread that he had this revolutionary new diet where you can eat, not be hungry and lose a lot of weight.

GRABER: A lot of those everyones were, women. Atkins basically bullied them into following his diet and would yell at them if he thought they weren’t, and he also used his practice as a dating pool and slept with a lot of those women he’d just made feel bad about what they were eating.

BITAR: He was sort of a man about town in New York City. He luxuriated in sort of the finer things in life. He rented homes in the Hamptons. He was a bachelor, a committed sort of bachelor until his late fifties when he married his wife, I think he was, was 57. And he saw his diet as being part of his lifestyle. You know, he was drinking, he was eating filet mignon. He was, you know, enjoying the finer things.

TWILLEY: So far so gross, but what was this revolutionary new diet? Oh wait, it’s the old diet—low-carb just wrapped up in a greasy new Atkins package. Here he is explaining it on a different documentary.

ROBERT ATKINS: It’s the evolution of really basic biochemistry, the fact that carbohydrates really can contribute to the formation of fat and that the restriction of carbohydrates can allow for a person to lose weight. And the revolution is really the urging of the populace to give a second thought as to this old hackneyed idea about… counting calories in order to lose weight.

BITAR: He saw carbohydrates, a low-carbohydrate diet. Which induced keto, ketosis in the first phase of it, the induction phase. As the sort of magic bullet for weight loss.

TWILLEY: Atkins was really the first one to introduce this word, ketosis or keto, in a mainstream popular weightloss kind of context. Technically speaking, not all low-carb diets are strict enough to make you go into ketosis, and even Atkins is only strict enough in the first phase, but keto was a key part of the Atkins magic.

VOICEOVER: With requests for copies of his diet flooding in, Atkins decided to publish it in book form. Dr. Atkins’ Diet Revolution hit the stores in 1972. And the diet revolution sold over 10 million copies and remains one of the 50 best selling books of all time.

GRABER: That is a kind of shocking statement. And not a happy one, if I’m going to be honest with you all.

TWILLEY: It makes me despair for humanity. The 50 best selling books of all time includes Dr. Atkins Diet Revolution?

GRABER: The thing was, people were looking for answers, and they loved that Atkins told them they could eat all sorts of things they usually thought they were supposed to avoid.

ATKINS: You’re eating things that you think, how could this be on a diet? How could these—this steak, this rack of lamb, how could this lobster and drawn butter be on a diet? And I could eat all the whole portion and come back with six, seven pounds off the first week.

BITAR: It seemed like everyone was following the Atkins plan. You know, no matter your class status, no matter your occupation, no matter your gender. It really brought men into the fold of weight loss dieting.

TWILLEY: Because of course steaks are much more manly than salads, which were what was on the menu for low-cal dieters. And honestly why shouldn’t men share in the fun?

GRABER: There were other low-carb diets floating around at the time in the 70s.

BITAR: So at that time we had the Air Force diet. The martinis and whipped cream diet. The drinking man’s diet. They used similar language that at can say they called carbohydrates the villain, but also emphasized the pleasures of eating, cooking. And it claimed that the diet, like the martinis and whipped cream diet, would allow you to enjoy eating as you lose weight. So really pushing back against the earlier idea that hunger alone was useful, that pain was productive. Like, Lulu Hunt Peters actually celebrated hunger and said, with every hunger pain, you know that you’re losing weight. So that’s a good indication. But the 1960s and 70s, you saw pushback against that by saying you, you don’t need to forego pleasure. You can enjoy eating. You can enjoy cooking. You can luxuriate in the pleasures of the table—but you have to do so by eating a low-carbohydrate plan, not a low calorie plan.

TWILLEY: To be fair, not all the low-carb plans were enjoyable or even compatible with continued existence. One of them was called the Last Chance Diet, it was invented by a guy named Roger Linn. He created shakes to make it easy to follow his diet. But unfortunately the name was a little on the nose.

EASTER: You were just supposed to eat—drink only those shakes, but he didn’t formulate them…well, with vitamins and minerals. And literally, like people died. Because they didn’t get adequate nutrition.

TWILLEY: For maybe obvious reasons, none of these other low-carb diets were as popular. Atkins was really it. Until along came the 80s.

BITAR: Low fat came back. The exercise mania also picked up.

[MUSIC]

JANE FONDA: Are you ready to do the workout?

[ALL CHEER AND CLAP]

BITAR: And I think that was not as compatible with um this sort of more luxurious way of eating that Atkins pioneered, that really sort of dwelled in the idea of like, you know, sitting down to your steak and your, your spirits and like, you know, bringing to mind like wood-paneled steakhouses and not sort of muscle beach, and California. It didn’t have that sort of fresh feel that I think a lot of diets in the, the eighties and nineties picked up.

FONDA: Stretch it out. One! Two! Three! Four! Five!

GRABER: It does seem like it’d be hard to put on some purple leg warmers and a leotard and do jane fonda after drinking heavy cream.

TWILLEY: For a while, the pendulum had really swung, low-carb was out and low fat was in. Everything—everything—was low fat. Even sausages.

SAUSAGE: I’m half the fat, proud of that, when I’m frying or I’m grilling.

VOICEOVER: Dannon low-fat yogurt. A good thing going for you. Every day.

WOMAN: Introducing Haagen Dazs low fat ice cream. Everything you want with just three grams of fat per serving.

GRABER: But yes, once again, there was some blowback, because people were still having a hard time losing the weight they wanted to lose. So they looked for something new, that was of course actually old. That’s coming up, after the break.

[BREAK]

BITAR: So 1992, Dr. Atkins publishes The New Diet Revolution. It spent five years on the New York Times bestseller list.

TWILLEY: It knocked Harry Potter off the top spot.

GRABER: Wow. But Atkins knew that a book and even his personal coaching in his office weren’t enough. People lived busy lives. He wanted to make sure everyone could follow his diet orders. So he started making pre-made snacks and low-carb bread and low-carb ice cream.

BITAR: His line of low-carbohydrate foods really brought this diet to the masses. So even if you didn’t have the initiative to pick up a diet book, you still might encounter these energy bars or these packaged foods in your grocery store.

TWILLEY: The first time round, in the 60s and 70s, a lot of Dr. Atkins’ patients were well-known and well-off. The second time round, the star power wattage was even more intense.

SHARON OSBOURNE: But then, I found Atkins. I lost 30 pounds, and I did it without starving myself.

GRABER: Sharon Osbourne made an ad for Atkins, Alyssa Milano did too.

ALYSSA MILANO: Everybody has it. That certain weight where you look and feel your best. Your happy weight. Atkins helped me get there, deliciously.

WOMAN: Early on in the Atkins diet, it was really all about Jennifer Aniston because, you know, she’s on TV every week and her picture is on every magazine cover.

VOICEOVER: The tabloids gleefully told us that Jennifer wasn’t the only one of the friends stars allegedly into Atkins. Matthew Perry’s famously fluctuating weight was also linked to the diet.

TWILLEY: This is from a documentary on Channel 4, from the height of second wave Atkins. The British film crew didn’t actually interview any celebrities, but they did find some random person from LA to comment.

ANGELENO: There’s a bagel shop in Brentwood that will scoop out the inside of the bagel and put in turkey or cream cheese. You will really not see bread at parties. You know, it’s just not polite. You barely ever see a potato in L.A.. I mean, potatoes are just gauche.

GRABER: Poor potatoes, I’ve always loved you, I’ve never considered you gauche.

TWILLEY: You are welcome in my house in Los Angeles anytime, Mr. Potato.

GRABER: Atkins was so popular that of course there were other copycats. I don’t know which diet a family friend was on at the time, but I remember him coming to my parents’ house and picking the cheese off the pizza and only eating that, leaving the rest behind. So sad.

TWILLEY: Back then I knew people on the South Beach Diet, I knew people on the Dukan diet which was French so you know obviously sophisticated.

PIERRE DUKAN: My diet starts with the attack phase. The results are so spectacular, you will feel motivated and encouraged. This phase is strict, but so short, and so effective on the scale, that you will feel no pain and no frustration.

GRABER: That sounds so great, why wouldn’t you want to try it?

TWILLEY: Side note, Dr. Dukan was later struck off the French medical register.

GRABER: And Atkins didn’t do so well at the end of his life. He had a heart attack in his early 70s—although he and his doctors insisted it had nothing to do with his diet—and then a year later he fell, went into a coma, and died.

BITAR: So there’s a lot of mystery surrounding Atkins’ health. When he died in 2003, he died— you know, it wasn’t old age, but it was premature for someone who wanted to have, you know, a long, long life. His widow would not allow an autopsy. Because there was speculation that he actually, had suffered from heart conditions earlier that may or may not have been the result of his diet.

TWILLEY: Atkins was dead, and low-carb started to seem so 2000. All the cool kids needed something newer and cooler.

BITAR: So, so paleo exploded around the turn of the decade, 2009, 2010, and so on.

GRABER: We’re not going to go into the story of what paleo is and how it exploded, very quickly the idea is to eat like our paleo ancestors. Yes, that makes no sense because they ate whatever was around them and that varied dramatically depending on where they lived. But the point is, that was a fad, and then people realized it was kind of silly.

BITAR: And then the keto people came over when paleo became so ridiculed as it wasn’t in vogue anymore. And keto picked up on a lot of the themes that paleo first brought in. So the best example of this is the diet leader, Mark Sisson, who wrote The Primal Blueprint in 2009, but then he transitioned to keto less than 10 years later, and he wrote the Keto Reset Diet in 2017.

TWILLEY: Yep, this is the latest and greatest version of the ketogenic diet—and this time around, it was less about scooping out bagels or drowning in lobster and drawn butter and more about these super fun 2000-teens buzzwords, like big data and productivity.

EASTER: The ketogenic diet became popular…you know, starting in say 2015 because of this weird intersection between Silicon Valley technology, Silicon Valley tech workers who are really into this idea of optimization. And like, we’ve got to optimize our lives in every, in any way we can.

GRABER: Michael says Tim Ferris is kind of the king of optimizing, he wrote a book called The Four-Hour Work Week and he followed that up with things like The Four-Hour Body and The Four-Hour Chef.

BITAR: This Tim Ferriss-ian ideal of optimal health where it, it’s not just about your six pack abs or getting into the BMI category. But rather like really becoming your best self in all of its facets.

TWILLEY: But how, you might be wondering, does ketosis help you be your best self? Well, as Shakespeare would say, let me count the ways.

EASTER: The sales pitch is that you’re going to burn more fat, but you’re also going to increase your focus. So by running on ketones, people report clearer thinking.

JOE ROGAN: Well, one of the first things that I noticed, the benefits, one of the first benefits was cognitive. Was, like clarity. Lack of fogginess towards the middle of the day, no desire to take a nap.

GRABER: Joe Rogan, otherwise known as the king of scientific accuracy—yes, I’m being extraordinarily sarcastic. He’s talking to a guy named Dom D’Agostino who’s a keto expert who’s been on both Tim Ferris and Joe Rogan’s podcasts.

DOM D’AGOSTINO: And for me, I could eat a keto meal in the morning and I can hammer out twelve hours of work in the lab and not even get any cravings to eat at all. And that for me, that translated into, you know, more grants, more publications, more work done in the lab. And I kind of attribute it in some way that, you know, my career has gotten a really big boost.

TWILLEY: He’s superman. All thanks to keto. Which was essentially just the first phase of Atkins, with a shiny new name.

BITAR: It’s a similar diet, but they just plastered it with science and pseudoscience. And one of the key things that made keto different, which is actually what Atkins advised in 1972, was to monitor and quantify the amount of ketones by using urine strips. So they’re sometimes called keto sticks. They’re not particularly expensive.

GRABER: You’d just dip these keto sticks in your urine and they turn shades of purple, and the color tells you the amount of ketones floating around.

BITAR: So that lent a real scientific air of credibility to the endeavor. That wasn’t just like embracing your inner caveman and, you know, pounding your chest. It was very scientific, it was very calculated. So that really picked up on this masculine… desire for what we call the quantified self.

TWILLEY: All this data was extremely sexy for the people who were into that kind of quantified optimized self thing. It gave the keto diet a crucial air of authority, and it also made it very shareable.

EASTER: People would also, I think, tend to share whatever their millimolars of ketones in their blood numbers too. I think becomes shareable to show that you’re in there. Basically people—like, you know, to back up about like why, why care about the numbers in the first place? Is, I think it confers an element of certainty to people. Like, okay, I’ve reached this. Like, the diet is working because I am, I have this… medical tool that is telling me I am doing this thing right. Not many diets can do that. And so this has this element of, you know… scientism almost.

GRABER: And the folks who did keto could see those numbers, those measurements, but they also saw something else.

EASTER: So when people go on ketogenic diet, they tend to dump a lot of water weight. That means the scale number is going to move really fast. So you could lose like ten pounds very quickly. Now it’s all from water. But still that’s like, I lost ten pounds, that’s very shareable.

GRABER: But it’s not all great.

JOSHI: There are downsides to the diet. The biggest pitfalls that I see are high cholesterol, and then also kidney stones which are also a big problem.

TWILLEY: Shivam told us you also have to think about what nutrients you’re missing out on because you’re not eating whole grains and fruits and beans.

JOSHI: The, the biggest one is fiber. Fiber has a lot of health benefits and, uh the ketogenic diet can be low in fiber, but because fiber is found in these foods that tend to have a lot of carbohydrates and you’re restricting carbohydrates, what happens to getting those benefits from fiber? Those in the ketogenic community say, well, you can eat low-carbohydrate, fiber rich foods. But I think that’s a challenge to meet the recommended fiber requirements.

GRABER: He says there are micronutrients that keto folks are missing, too. And Adrienne points out that you often feel pretty crappy physically when you start doing keto.

BITAR: The downsides to the ketogenic are many. From a health perspective, there’s the nausea, there’s the constipation, there’s the GI problems. From a social perspective, it completely limits—unless you’re only socializing with fellow keto fans—limits where you can go out to eat, you know, how you can socialize, how you can celebrate events because your diet is so limited. And then sitting here with the vantage point of 2023, we definitely know about the environmental and climate impacts of a high animal content diet. That eating animal products is just—this isn’t an argument, this is just a fact—is, is very bad for the environment. And eating lower down on the food chain, they’ve been saying this since the 1970s, is, is far better for the environment, and for greenhouse gas emissions. So there’s the health aspect, there’s this sort of social aspect, there’s the environmental aspect. There’s many, sort of, downsides to following ketogenic diet. Plus it’s very difficult.

TWILLEY: All of this sounds terrible. Remind me why people are doing it again?

GRABER: Well, a lot of people want to lose weight, and this whole keto story sounds super compelling. I mean all the websites promoting keto aren’t going around hyping the downsides of the diet.

TWILLEY: But ignoring for a moment all of those downsides, which are hard to ignore, and assuming that you do want to lose weight—we already pointed out that people on keto lose weight at the beginning, but it’s just water weight. So—is this diet useful over the long-term for people who want to lose weight?

JOSHI: When you look at all these studies, these really well done, randomized controlled trials published in big name journals that have been done over the years that have compared various diets. There’s these controlled trials that look at the standard American diet, and Atkins diet, and then they look at a Mediterranean diet, and they look at other diets. And the studies vary according to which diet they looked at, but, no matter what the study is, what the diets are being compared, the most important thing is that people are restricting calories. And that is what leads to weight loss, which is not surprising.

EASTER: I could say, eat foods that begin with a letter B. Only that. And by doing that, you would get someone to eat less food.

TWILLEY: Basically anytime you restrict what you eat and eat less, you lose weight. The big question is whether you can stick to it or not. There’s no doubt that keto is challenging—it’s really restrictive, like Adrienne said, it really limits your social options.

GRABER: People who are on it sometimes say they can stick to it because it helps to control hunger, but there’s no data to support that, and frankly it could be the placebo effect. They’re working really hard to stay on this diet, they’ve already bought into the fact that this is going to work. And as we talked about in our recent episode on hunger, there’s a lot we don’t understand about it.

JOSHI: The whole appetite suppression area, I question, because… it’s hard—how do you measure appetite suppression? I’ve seen people say that high-protein diets can suppress appetite. People have said high fat diets can suppress appetite. Some people say that eating high carb diets can even suppress appetite. I have not seen really well designed studies showing that ketogenic diet suppress appetite.

TWILLEY: So color me shocked but it seems like—wait for it!—keto does not in fact have magical powers when it comes to weight loss and becoming superman. Or woman. I mean, of course it doesn’t.

EASTER: My opinion is like if there was a diet that conferred such grand, incredible benefits beyond any other way of eating, we would all be doing it.

GRABER: So nothing magic about it—unless, as it turns out, you have one very particular disease. That’s coming up after the break.

[BREAK]

EASTER: So I believe as far back as like 500 BC, people noticed that epileptics who didn’t eat for like two days, they would stop having seizures. So there’s, okay. Great. But the advice can’t be like, okay, if you’re epileptic, just don’t ever eat again, because then you got another problem on your hands.

TWILLEY: Indeed you do. But in the early 1920s, some epilepsy doctors figured out what was happening metabolically when their patients were fasting—that they were burning fat and producing ketones. And they were the ones to figure out that if you cut carbs so that your body was forced to burn fat, you’d also produce ketones. And maybe this would work to help calm seizures without the inconvenience of starving.

MCDONALD: But it was Doctors Wilder and Winter at the Mayo Clinic in Rochester who first sort of formalized the diet and sort of put it into human use. At the time for a treatment for, for seizures and epilepsy. And they published one of the first reports about efficacy of the diet for, for seizure control in the the late 1920s, early 1930s.

GRABER: Tanya McDonald says it was popular for a while back in the 1900s before it was replaced.

MCDONALD: Not too long after the ketogenic diet came out in the 1930s, one of the first anti-seizure medications, Dilantin or Phenytoin, and then subsequent to that, phenobarbital came out. And then a number of other anti-seizure medications. I think we have in our arsenal, thirty different anti-seizure medications at this point? And so yes, because of the ease of use of a pill compared to a diet, for many patients the ketogenic diet did sort of fall out of favor in that time period.

TWILLEY: A few doctors still used it but it wasn’t mainstream and it wasn’t really being researched. Until it popped back on people’s radars again, thanks to none other than Meryl Streep.

BROTHER: Mom, mom, come quick, somethings wrong with Robbie! Hurry, Mom! Hurry! Mom!

[DRAMATIC MUSIC]

GRABER: Meryl starred in a movie in 1997 called First Do No Harm that was based on a true story about a kid with epilepsy who didn’t respond to any of the medications available. It was the keto diet that saved him.

MCDONALD: And since then literature, publications, and knowledge about ketogenic diets for, for epilepsy, not only in kids but now also in adults has grown.

GRABER: To the point where these days, Tanya regularly uses keto to treat some of her patients.

MCDONALD: And so I tend to think about it in any person with epilepsy that has failed two drugs or meets criteria for drug resistant epilepsy.

TWILLEY: This is actually a lot of people. Tanya told us that about a third of patients with epilepsy don’t respond well to medication. And epilepsy is thought to affect 68 million people around the world.

MCDONALD: Right, so it’s a pretty large chunk of patients that could potentially benefit from a ketogenic diet.

GRABER: Tanya works with both children and adults. But as we’ve already pointed out, this diet is hard to stick to. Tanya says about half of her adult patients stop, for some of them it’s because it’s not working for them, but for most of them it’s just because it’s just really hard. It’s a little easier for kids to follow it because their parents are preparing their meals. Often they only have to be on it for a few years to make a difference. And Tanya works carefully with her patients to avoid the health risks that Shivam talked about.

TWILLEY: One thing you might be wondering at this point is how on earth ketones work to help prevent seizures. The answer is, we have some clues but we don’t know for sure.

MCDONALD: There have been a number of studies that suggest that ketones themselves can dampen abnormal electrical excitability in the brain. And that’s basically what a seizure is. There have also been some studies that show that ketones coupled with reductions in carbohydrates can also have some anti-inflammatory properties. And there’s some thought that in some forms of epilepsy, excess inflammation can lead to the development of seizures. And so there’s a lot of varied hypotheses as far as which impacts the ketogenic diet can have. But there is no one solid mechanism as far as, this is the immediate way that it works for all patients with epilepsy.

GRABER: Despite this lack of certainty, scientists have been looking into other ways that keto might have medical benefits in the brain.

MCDONALD: There’s some studies that are looking at the ketogenic diet for brain tumors. Particularly like glioblastoma for example, which is a, a key brain tumor in adults that has very poor outcomes with standard of care therapies. And the thought here is that tumor cells like glucose. They like sugar as a principal fuel source, right. Whereas your native cells that aren’t tumors can use either glucose or ketones, right? And so by reducing your intake of glucose, you’re sort of trying to starve the tumor cells. And only feed your healthy cells. And so that might be one mechanism where they could be beneficial for helping to treat your potential brain tumor.

TWILLEY: Unlike for seizures, *this* use of the keto diet as a medical treatment hasn’t been proven yet, it’s still a theory.

MCDONALD: There’s also some look at such diet therapies for dementia or other sort of neurodegenerative disorders, for Alzheimer’s disease.

GRABER: On the other hand, Shivam told us there’s some data suggesting that consuming a lot of animal and saturated fat is not good for long-term cognition and risk of dementia.

MCDONALD: None of these other fields have had the amount of literature that has been reported and studied as epilepsy does. And so the work is still new in a lot of these areas and a lot of clinical trials are actually underway for a lot of these other conditions.

GRABER: Unsurprisingly, as you hear frequently on Gastropod, more research is needed.

TWILLEY: Meanwhile, unless you have drug-resistant epilepsy, Michael says keto is over. The tech bros and the optimizers have found a new belief system.

EASTER: I think a lot of them have now moved on to the carnivore diet.

TWILLEY: Which literally excludes all produce. It’s zero carb.

GRABER: If it’s possible, this sounds even worse. But, so keto had its time and place—it was very of the moment.

EASTER: I think keto allowed us to get data that was something that that crowd really liked and wanted and felt like could bring them into a better place. And then they got asked to go to lunch at Subway and the train derailed. And so you’ve seen keto sort of rise and fall, depending on the story.

TWILLEY: At the end of the day—unless, again, you’ve got drug-resistant epilepsy, that’s what this is all about. Stories. Stories we get told and we tell ourselves.

BITAR: If I believe that going on this diet, that eating eggs and duck and bacon and drinking whipped cream is going to help me with my stress level. Likely it will. Right? That’s just who we are as humans. We’re very malleable.

GRABER: We’ve said this before on Gastropod: these types of stories might sound kind of harmless, but diet culture in general is actually really harmful. To our surprise, this diet turns out to be able to help some people with epilepsy live happy and healthy lives. For the rest of us, diet culture is so pervasive in our society that it’s easy to get swept up in it, but diets and this whole thought pattern can genuinely hurt us, both mentally and physically.

BITAR: And that’s where it gets really… sort of insidious. Because we all have problems, right? Even if it’s not with our weight, it’s with our brain or stress or relationships. So we all are looking for, you know, a fix. And that’s where the diet can really speak to not just those who are concerned about their weight, but those who just are longing for something more, something better.

[MUSIC]

TWILLEY: Thanks this episode to listener Kathryn Elkins for your suggestion and for listening! It’s always fun to hear from you all!

GRABER: Thanks also to all our guests this episode: Adrienne Bitar, Michael Easter, Shivam Joshi and Tanya McDonald. You can find more about their research, their books, and their reporting on our website gastropod.com

TWILLEY: And of course thanks to our awesome producer, Claudia Geib. We’re back with a fishy tale in just a couple of weeks, ‘til then.