Can Keto Help You Live Longer?

Matthew: There's a lot of reason to believe that this diet might be valuable. But there's still so much left to learn about how to use it, who to use it with, and is it really doing what we think it might be doing. So a lot more to learn, but a lot of things to really be optimistic about.

Matthew: Never make any hard support for any brand.

Unknown: Pick yourself up and keep moving through the pain. Keep moving forward. That's what you do. Great. Thank you.

Matthew: It all comes down to today.

BrentWelcome to Death Clock. I am your host, Brent Franson. And today we speak with Doctor Matthew Taylor about the keto diet. Doctor Taylor is at the Brain Nutrition Lab at the KU Medical Center at the University of Kansas, where they study how nutrition can be used to prevent Alzheimer's and other neurological conditions. This conversation is really a keto 101.

BrentWe go through what exactly keto is, what's happening in the body when you're in a state of ketosis, the foods that you can and cannot eat if you want to be on keto, and then all of the benefits. There's really a shocking number of benefits across risk reduction for type two diabetes and cancer. There's some early evidence that it's preventatively helpful for Alzheimer's.

BrentAnd in the treatment of Alzheimer's and slowing onset, we really just do a top to bottom on keto. He's a wonderful guest. I hope you enjoy.

BrentDoctor Matthew Taylor, welcome to the show.

Matthew: It's great to be here. Thank you.

BrentSo today we are talking about ketogenic diets—keto. I think we should just try to go top to bottom on this. It feels to me like it's the perfect diet on paper, but it's hard to put in practice. So I want to talk about all things keto. But before we do that, can you give us a sense of your bio?

Matthew: Yeah. So I'm an associate professor at KU Medical Center in Kansas City, Kansas. I've been working with the ketogenic diet for a little over a decade now—it's hard to believe it's been that long. I primarily do clinical trials in the prevention and treatment of Alzheimer's disease, but I collaborate with a lot of nutrition folks that have interest in other conditions.

Matthew: So we've done some ketogenic diet work in people that are generally healthy. We've done some work in traumatic brain injury, and we're looking at some other areas as well.

BrentOkay. Wonderful. So let's just start with the very basic question of what is the ketogenic, the keto diet.

Matthew: It's got a really long history that evolved out of fasting, where a long time ago, you could produce ketones through just not eating for a very long period of time. So that was sort of the original ketogenic diet. But there's been an evolution in our understanding of how we metabolize different macronutrients like fat, carbohydrate, and protein.

Matthew: And we can manipulate those particular components to induce a state of ketosis, which is producing ketones in the body through the liver. That's primarily done through increasing your fat content in the diet drastically and reducing carbohydrate content. When you think about a normal American diet, it's usually about 50% carbohydrate as the energy that we consume.

Matthew: We're talking about reducing that down to about 5% or less. There are some variations of the ketogenic diet—some stricter versions and then more liberal versions—and that can affect the level of ketosis that you have in the blood. But that's the general concept: we bring fat content up to about 70% of energy or more, and bring carbohydrate intake down to about 5%.

BrentSo is it correct to say that our body basically has two fuels for producing energy—one of them is sugar and one of them is fat? If we have a traditional diet, the American diet that has a lot of carbohydrates, then we are operating in a system that is burning sugar for energy. When we eliminate those carbohydrates and that source of sugar, then we switch into the second mode that we call ketosis.

BrentWhere the body is burning fat to produce energy. And that second mode of energy consumption is just much healthier in a bunch of ways. Is that oversimplified?

Matthew: Well, that is a simplification of it, but you're right. We're primarily going to be using glucose, the sugar, in a carbohydrate-rich diet, and then switch to what we consider the alternative fuel source of ketones by adopting this ketogenic diet approach. I will say that there are some conditions where ketones look to be very beneficial for treatment.

Matthew: And then there's probably a lot of cases where, in general health, the ketogenic diet might be a very healthy way to eat. But there's still a lot we need to learn about whether we can simplify it as being the healthier diet versus a non-ketogenic diet, because there are a lot of really healthy non-ketogenic diets as well that we're interested in from a nutrition perspective.

Matthew: From an energy metabolism standpoint, it does seem that ketones, especially in certain circumstances, could be very beneficial for providing fuel—they might burn a little bit cleaner than glucose does. In times that you have oxidative stress, like reactive oxygen species and inflammation that are damaging to the body...

Matthew: There are indications that the ketogenic diet might be the right way to go because it helps tamp some of that down.

BrentMy understanding—at least the simplest way of understanding keto or its health benefits—is that sugar and desserts aren't good for us, and carbohydrates like pasta basically break down into sugar. So a keto diet is a low-sugar diet.

BrentWhen we say sugar, we're talking about glucose. But you're talking about the benefit of ketones specifically. So what is a ketone? What is its role when we're not in ketosis? Why are ketones specifically good for us outside of reducing sugar consumption?

Matthew: We're always doing both at the same time depending on how you're eating and how long it's been since your last meal. You might switch over to ketone metabolism a bit more, but even on a ketogenic diet, you're still using glucose to some degree—just a lot less.

Matthew: Our bodies are already doing both at the same time in any physiologic state. But if you eat a ketogenic diet, it inherently drops sugar intake, which has its benefits. When we eat high fat and low carbohydrate, those fats bombard the liver with energy.

Matthew: Our liver needs to do something with that fat coming from the diet, so it shunts it into a pathway where it turns a lot of it into ketones. There are a couple we focus on: one is beta-hydroxybutyrate, which is the primary ketone circulating in the blood.

Matthew: There's another called acetoacetate, and a third called acetone. Beta-hydroxybutyrate and acetoacetate levels stay in flux with each other, rising in the blood to provide energy to tissue where needed.

Matthew: Organs like muscle and the brain require lots of energy, and ketones can provide that energy. They burn clean and seem to be a really good energy source.

Matthew: They also serve as signaling molecules. They interact with machinery in our body responsible for regulating inflammation, or upregulating antioxidant systems. They have several other signaling components as well.

Matthew: When thinking about prevention or treatment of Alzheimer's disease: brains don't use glucose quite as well as we get older. There are indications that ketones may be really important for maintaining brain energy metabolism and optimizing brain health across the aging spectrum.

Matthew: These ketones are doing a lot of important things. They are small molecules that come from fat; the liver turns that fat into ketones, which then go on to perform fascinating physiological processes.

BrentWhat is the difference between sugar and glucose? Can we think of those two terms interchangeably? Is glucose just another word for sugar that's been processed by our digestive system?

Matthew: There are different types of sugars. Generally, we think of sucrose—table sugar used in baked goods or coffee. Once consumed, sugars are converted into the most basic form of sugar, which we call glucose.

Matthew: When your body wants fuel to perform any function, such as brain energy, it looks specifically for glucose.

BrentThe body takes in sugar and converts it into a universal energy currency required to generate energy. Moving on to keto: what is on the menu, and what is off the menu from a specific foods perspective?

Matthew: We eliminate anything high in sugar, so desserts are out. The goal is to lower sugar and overall carbohydrate intake, because all consumed carbohydrates eventually turn into glucose—whether sugar or wheat products like bread.

Matthew: There is a massive decrease in those foods, near elimination depending on how strict you are. Foods to focus on include healthy fats: avocados, olive oil, and even saturated fats, which our bodies process differently when on a low-carbohydrate diet.

Matthew: Saturated fats can raise ketone levels well, so items like butter or coconut-based products work. My research lab is particularly interested in understanding how to approach this in a very healthy way.

Matthew: We want to avoid bolstering fat solely through cheese, mayonnaise, and bacon. Those can increase dietary fat to reach ketosis and have a role, but we focus on healthier fats.

Matthew: Healthy fat sources include fatty fish like salmon, rich in omega-3s. Meat is also common on the diet.

Matthew: Vegetarians can follow the diet, though it is tougher without meat as a primary fat source. For carbohydrates, we encourage participants to consume non-starchy vegetables.

Matthew: Broccoli, cauliflower, and greens contribute high nutrient density with low carbohydrates. A handful of berries—blueberries, blackberries, or strawberries—is fine for added nutrition.

Matthew: We also encourage plenty of water, as the diet causes significant fluid loss through urine. Maintaining fluid status is essential.

BrentIt's a strict diet in terms of menu options, and it seems binary: you must dramatically reduce carbs and sugars to enter ketosis and gain benefits.

BrentThere isn't a version where you reduce carbs slightly and gain full benefits; there's a non-linear increase in benefit once transitioning into a ketogenic state.

Matthew: That's a good way of thinking about it. Ketones are key to these benefits, and response varies by individual. Some can be more liberal with carbs while still producing high ketone levels.

Matthew: Others must be strict. Reaching ketosis involves reducing carbs while increasing fat. People often forget to add fat because we're trained to avoid it.

Matthew: Adding fat is crucial to bolster ketone status. Once you cross into ketosis, that's when you start gaining the benefits of the diet.

BrentHow long does that transition take? If I start tomorrow with eggs for breakfast, chicken salad for lunch, broccolini and steak for dinner, nuts for snacks, and plenty of water...

BrentQuick question: is any alcohol keto-friendly, or is alcohol completely out?

Matthew: Some data suggests alcohol can bolster ketones. It depends on carbohydrate content; pure grain spirits are the most ideal.

BrentSo the hard stuff—like vodka?

Matthew: Yes. Case studies show that individuals consuming moderate alcohol became more ketogenic on a keto diet.

BrentBeer is out, but what about wine?

Matthew: Wine works if you monitor carb content. Very dry white wines are best because they have the lowest carbohydrate content, followed by very dry red wines.

BrentFor spirits, you mean having a gin, vodka, or tequila neat?

Matthew: Right, in small amounts. Overdoing it can kick you out of ketosis, but a small amount can benefit ketone levels.

BrentIf I start tomorrow, how long does it take to transition from my current metabolic state into a ketogenic state?

BrentHow do I know when I've transitioned? Is there a J-curve with the 'keto flu' where I feel worse before feeling better? What should I expect over the coming days?

Matthew: It varies by person, but eating to match energy needs on a keto approach usually induces robust ketosis in a couple of days. The longer you follow it, the more your body ramps up ketone production.

Matthew: You lower glucose and insulin levels by restricting carbohydrates, deepening ketosis over time. Supplements can also acutely induce ketosis.

Matthew: Medium-chain triglycerides (MCT oils from palm or coconut oil) raise ketones without full dietary changes. However, the diet systemically alters metabolic infrastructure, whereas supplements only temporarily bolster ketone levels.

Matthew: Adding supplements to a keto diet helps achieve ketosis faster, allowing ketone levels to jump more quickly.

Matthew: Strict dietary changes take a few days to reach robust ketosis, as muscle and liver glycogen stores must deplete to lower blood glucose.

Matthew: Fasting for half a day to a day before starting keto accelerates entry into ketosis. Regarding the keto flu: it's a common transition phase.

Matthew: It isn't an illness, but a feeling of fatigue, nausea, or headaches during adaptation from high to low carbohydrate intake.

Matthew: We can mitigate these symptoms because they stem from fluid and electrolyte shifts. Drinking plenty of water is essential.

Matthew: Because water excretion increases, sodium, potassium, and magnesium drop. Replenishing these electrolytes minimizes adaptation symptoms.

Matthew: People hesitate to add sodium, but on keto, adequate sodium intake is necessary to balance changing electrolyte levels.

BrentWhen do flu-like symptoms start, how long do they last, and are they harmful?

Matthew: They aren't harmful or causing major damage—just uncomfortable during the adaptation phase. Symptoms typically start a few days in as metabolism shifts to ketones.

Matthew: Without electrolyte management, keto flu symptoms usually last a few days to a week.

Matthew: Educating participants on adding sodium and electrolytes drastically reduced keto flu complaints in our studies.

BrentSo does it follow a J-curve? You feel worse during the keto flu, but once past it, you feel better than baseline?

Matthew: Yes, people frequently report feeling better on keto. The J-curve describes it well: temporary discomfort followed by feeling great if you respond well.

Matthew: Having followed keto myself, ketones can induce a mild euphoria or hyper-focus that signals you're in ketosis.

Matthew: People describe a cognitive boost and excellent focus when ketones are elevated.

BrentWhat is the role of fasting in keto? They are often combined, as keto grew out of fasting practices. Is stacking keto with intermittent fasting ideal?

BrentDoes fasting accelerate or compound keto benefits, or is it optional?

Matthew: Fasting complements keto well. Fasting alone generates ketones by depleting glycogen and reducing insulin and glucose levels.

Matthew: Combining both addresses distinct physiological mechanisms: keto provides new fuel via high fat and low carbs, while fasting relies on depletion.

Matthew: Epilepsy research suggests fasting may favor acetoacetate production, whereas a ketogenic diet favors beta-hydroxybutyrate.

Matthew: Different approaches promote distinct ketone bodies, which possess unique signaling properties.

Matthew: Varying ketone levels might offer specific therapeutic value when treating neurological conditions.

BrentWhat do we know about specific fasting schedules? A 16:8 window is common. When is it best to position that 8-hour eating window?

BrentDiscussions used to favor skipping breakfast (eating noon to 8 p.m.), but recent views highlight the importance of morning nutrition over dinner.

BrentSkipping dinner has social and family costs. Which eating window is scientifically better—morning or evening?

BrentAnd if you have to choose between the PM eating window or the Am eating window, what do we know about which of those is better?

Matthew: Intermittent fasting data evolves rapidly. Extending an overnight fast past waking feels straightforward initially.

Matthew: It feels challenging for a few days, but hunger signals adapt quickly to the schedule.

BrentJust make it to lunch?

Matthew: However, growing interest focuses on morning cortisol and hormone regulation (testosterone, estrogen).

Matthew: Eating in the morning may help preserve hormonal balance throughout the day.

Matthew: If designing a study combining keto and fasting, I would focus on evening fasting windows. The 16:8 protocol remains the most standard and effective for boosting ketones.

Matthew: That seems like a pretty appropriate approach. And it would and it would help bolster the ketone levels, especially if you're, if you're following a ketogenic diet.

BrentMorning fasting is tough when exercising early. Sleeping in a fasted state also improves sleep quality, supporting the PM fast despite social drawbacks.

BrentSo it seems the p m fast is the right fast. You just deal with this tricky, just cultural societal thing, which is dinner is an important moment for families. It's an important moment to get together with friends. And we're we're just not really that tolerant of somebody sitting around and not eating. And so that seems to be the little bit of the wrinkle with, the p m fast.

Matthew: Every routine presents challenges. In our Alzheimer's studies, entire household units often adapt to the protocol together, making adherence much easier.

Matthew: But, you know, it's kind of also, when we do studies, oftentimes our whole, the whole family unit. So we do a lot of Alzheimer's work. So what spouses and then family members that are part of this whole study process, they generally adapt to whatever the, the study participant is doing, because they do it as a sort of a whole sort of unit, which is really helpful when we're doing studies.

Matthew: It makes it much easier for, for people to, to follow these types of, diet patterns. But when you think about having kids and family and things like that, you know, they may not be they may not be fasting as well.

BrentPrimary criticism of keto centers on difficulty with adherence rather than efficacy. As a keto researcher, why aren't you on full-time keto, and how do you view adherence challenges?

BrentBut but first, I think, you know, the primary criticism of keto seems not to be that if you adhere to it, it is healthy and that you'll see a lot of health benefits. It's that it's very difficult to adhere to. And here you are a keto researcher and you've said, hey, I've, I've done the keto diet at times in the past.

BrentSo I think there's something to be learned. And, you know, Doctor Taylor, who spends his career studying this doesn't isn't full time keto. So you know why aren't you full time keto? And what do you think about this adherence difficulty, either for yourself or just across the people you see in the studies that you're doing?

Matthew: During a three-year pilot study in Alzheimer's, I stayed in continuous ketosis alongside participating families, and I really enjoyed it.

Matthew: Knowing what to eat is a major advantage. Unsurety about allowed foods is the biggest barrier for most people.

Matthew: Dietitians play a vital role in guiding study participants so they adhere strictly to trial protocols.

Matthew: During those three years, I felt hyper-focused and productive in ketosis. Re-entering ketosis now still brings that clear, acute sensation.

Matthew: Generally, I eat a Mediterranean-style diet because I enjoy variety. Scientifically, I study keto, but I don't promote it as a universal diet.

Matthew: We don't fully understand individual cholesterol response on keto. Whether elevated cholesterol on keto is harmful requires further study.

Matthew: Individual responses vary widely: some gain significant cognitive focus, while others feel no change.

Matthew: Future research should clarify genetic and metabolic factors determining who thrives on keto versus high-carbohydrate diets.

Matthew: There's people that describe feeling nothing by being on the ketogenic diet. So it would be really interesting to understand, like who those people are. He responds to it. Who doesn't? And then also understanding things like, lipid metabolism, carbohydrate metabolism, the genes that regulate that, that the genetics that regulate that, those would be really important information for us to be able to decide this person would do a lot better on a ketogenic diet, and this person would do a lot better on a high carbohydrate diet.

Matthew: Keto offers compelling science regarding brain energy metabolism and tumor growth suppression (since tumors rely heavily on glucose).

Matthew: As we age, ketones can preserve brain health when glucose utilization drops. We must identify optimal candidates to prevent potential adverse responses.

Matthew: You know, ketones may be really, really important for, for brain health as we age. So, where I'm, where I'm at with this is we we need to know a lot more about who to put on the diet. Who is it really going to benefit? Who's going to respond well to it? And who might actually have an adverse response to it because there are people that adversely respond to the ketogenic diet.

Matthew: Evaluating broad systemic biomarker responses will guide safe, targeted recommendations.

Matthew: We talk about biomarkers like cholesterol and, you know, all sorts of different health parameters like we there's a there's a big picture, systemic picture that needs to be thought of when it, whenever it comes to putting a person on the diet.

BrentKeto shows strong evidence for reducing risk across three key health areas: type two diabetes (improving glucose, insulin, HbA1c), inflammation, and dementia.

BrentAnd we're looking at biomarkers like blood glucose or insulin sensitivity or hemoglobin A1, see that we see very clear and positive benefit. There, inflammatory markers that will affect risk of dementia and risk of type two diabetes and heart disease, like, high sensitivity C-reactive protein. We're going to see benefit there. And then on dementia, you know, I would assume maybe an Omega index.

BrentRegarding heart disease markers (LDL, ApoB), increased fat intake can raise cholesterol, though its exact relationship to disease risk is being re-evaluated.

BrentBut your call out there is, we're starting to question what we know about, quote unquote, bad cholesterol, high cholesterol in and of itself isn't disease. Like I'm somebody who has high cholesterol, but I don't have any plaque in my arteries. From a, you know, a, coronary angiography. You know, we don't know. There's something to learn there.

BrentDefinitely. Some people on keto do see an increase in quote unquote bad cholesterol. Is all of that fair to say?

Matthew: That is accurate. Reducing carbohydrates directly improves glycemic markers relevant to diabetes by shifting energy reliance away from glucose.

Matthew: You're using alternative fuel. So yeah, I it's very accurate there.

BrentCancer cells rely heavily on glucose rather than ketones, so ketosis can slow tumor progression and enhance cancer treatments.

Matthew: Glucose acts like fuel for tumors, whereas normal cells adapt efficiently to ketones.

Matthew: I think you mentioned dementia is another one. Yeah.

BrentAs an ApoE e3/e4 carrier with family history, what is known about keto regarding genetic predispositions and Alzheimer's prevention?

Matthew: Clinical trials show cognitive benefits from keto in Alzheimer's patients, along with positive changes in inflammatory and protein biomarkers.

Matthew: Larger multi-center trials are necessary to validate the therapeutic potential observed in smaller studies.

Matthew: Data suggests benefits in early Alzheimer's and Mild Cognitive Impairment (MCI). ApoE e4 represents the strongest genetic risk factor for Alzheimer's.

Matthew: Not everybody who gets who has mild cognitive impairment will have Alzheimer's, but, but they're at high risk of having it. You posed a question. You mentioned ApoE e. That's ApoE e4 is the strongest genetic risk factor for, having for having an Alzheimer's diagnosis later. Those that have two copies of that, maybe for the older.

Matthew: ApoE alleles regulate fat and carbohydrate metabolism, highlighting diet's key role in prevention and treatment strategies.

Matthew: Early indications suggest non-e4 carriers may show faster cognitive improvements, though e4 carriers demonstrate significant molecular changes on keto therapies.

Matthew: But I again, I just want to urge caution. We don't we don't have enough evidence to say that we know this. We just are seeing trends in that direction. But we also have some really good mechanistic data that suggests that, those that have ApoE e4 alleles that follow a ketogenic diet may have really profound molecular changes, things that are, you know, changing on a molecular level that may be in time frame on this might be really important to like, how long do you follow this diet to see benefits?

Matthew: Longer-term studies will help quantify these physiological responses and determine ideal diet duration for maximum cognitive benefit.

Matthew: How long do we need to follow the diet? Who responds best? There's a lot of there's a lot of really interesting, stuff to learn here. There's a lot of reason to believe that these that this diet might be valuable. But there's still so much left to learn about how to use it, who to use it with.

Matthew: And is it really is it really doing what we what we think it might be doing? So a lot more to learn, but a lot of things to, to really be optimistic about.

Brent: Where can listeners find your work and learn more about keto?

Matthew: You can visit the KU Medical Center website or search for the Brain Nutrition Lab, where we post information on our ongoing clinical trials.

Matthew: And we really want to we really want to understand the the role of, of the diet, the role of chemotherapies in, prevention and treatment of Alzheimer's. So hopefully that will come around. So I think you can Google search the brain nutrition lab. That's my lab. And we should here soon have some some more information there.

Matthew: Podcasts and published literature provide good starting points for exploring the diet and assessing whether it fits individual needs.

Matthew: I think it's I think it's a really interesting one, but, still a lot to learn. Wonderful.

BrentDr. Matthew Taylor, thank you so much for your time and for the research you do.

Matthew: Yeah. Thanks for having me. This is a lot of fun.

BrentDeath Clock is recorded in Boulder, Colorado, and San Francisco, California. Produced by Patrick Gudino, music by Patrick Lee, and hosted by Brent Franson, founder and CEO of Death Clock.