#845: How to Use Ketosis for Enhanced Mood, Cognition, and Long-Term Brain Protection — A Practical and Tactical Guide with Dr. Dominic D'Agostino (Plus: Deconstructing Tim’s Latest Keto Experiment)

Hey friends, Tim Ferriss here. Today’s a fast, practical deep dive on ketosis with Dr. Dominic D’Agostino—why it helps, how to do it, what to avoid, and how I’m tweaking my own month-long experiment with continuous glucose and ketone monitoring.

Why I even bother: once my blood ketones pass roughly the low-to-mid point range, I need less sleep, wake up clear, feel sharper all day, skip the afternoon crash, and my mood steadies without losing the highs. Potential long-term upsides might include neuroprotection, lower inflammation, and support alongside cancer care.

Dom’s quick bio: he’s a tenured researcher focused on metabolic therapies for neurological conditions, performance, and more, with funding across DoD, NIH, and others. He also walks the talk athletically.

I’ve been in ketosis for 18 days and want the best-evidence benefits and what’s next on the horizon. What’s the short list?

Ketosis mimics many fasting benefits without the muscle loss and fatigue of deep caloric deficit. In the brain, it lowers glutamate, raises GABA, calms hyperexcitability, and reduces seizures across causes, which explains its draw in metabolic psychiatry.

Outside the brain, why else would someone try it?

Weight loss and better blood pressure often show up first due to its diuretic and natriuretic effects. It lowers insulin, ramps fat burning, triggers ketogenesis, and ketones act as metabolic signals with real-world impact, which is why exogenous ketones have so many active trials.

A personal story: ketosis erased severe cognitive and joint symptoms after a tick-borne infection when nothing else worked, and friends saw similar turnarounds. What’s the possible mechanism?

Borrelia is essentially fully glycolytic, so restricting glucose stresses its energy supply. Elevated beta-hydroxybutyrate also boosts adaptive immunity, which together can suppress or help clear pathogens; people report benefits with other inflammatory infections too.

For cancer care, can ketosis substitute for fasting, or is it a smaller slice of the benefit?

It depends on weight and status. Overweight patients often do well with fasting or calorie-restricted keto, while leaner patients should stay eucaloric but raise ketones for anti-inflammatory, immune, and neuroprotective support; it’s not a cure, but it can slow highly glycolytic tumors and improve responses to standard therapies.

I use ketosis for mood stability and clarity, and I’m hoping periodic blocks provide durable benefits for brain health given heavy family risk. Does cycling keto create lasting metabolic changes, or am I hand-waving?

There’s good support for lasting effects. Think metabolic memory: repeated ketosis boosts fatty acid oxidation, mitochondrial function, and adaptation so future transitions are faster and benefits come easier.

My current protocol: daily intermittent fasting made the switch to keto painless this time—no fog, just two meals a day. A go-to cheap meal is canned mackerel with MCT oil and apple cider vinegar; the rest is simple proteins, big salads, and low-carb veggies.

Small fish like jack or chub mackerel are budget-friendly, rich in omega-3s, and low in heavy metals. Buying by the case drives cost way down.

Here’s a head-scratcher: I often feel fantastic with low glucose but see ketones stuck around 0.1 to 0.4 on sensors and even fingersticks. Am I actually failing at ketosis, or is this a false negative?

You’re likely running lean with high insulin sensitivity and high ketone utilization, especially in a calorie deficit. Blood readings reflect production minus use, so fitter people can show lower blood ketones while tissues and brain are using a lot; breath acetone often tracks this better.

So a person producing ten “units” could show two in blood if eight are rapidly used. Breath meters read acetone from acetoacetate, right?

Yes. Acetoacetate can decarboxylate to acetone, and breath acetone can be a better marker of deep fat use when calories are low.

About protein and gluconeogenesis: how do I avoid protein knocking me out of ketosis?

Liquid protein spikes amino acids fast and suppresses ketones. Slow the gastric exit with fat, fiber, and salt—add MCTs and mixed fibers—so amino acids trickle in, blunting insulin and gluconeogenesis.

If I crush a massive bunless cheeseburger, could the meal size alone kick me out?

Huge meals activate stretch receptors and sympathetic tone, which can nudge gluconeogenesis; salty meals also expand plasma volume. A brisk 15 to 20 minute walk right after eating can flatten the later rise by activating GLUT4 without much insulin.

On sensors: my continuous ketone monitor often reads low no matter what. Any tips?

Interstitial ketone sensors can drift after the first week, and calibration with a blood meter matters. Use periodic fingersticks to sanity-check, and remember breath and blood can diverge when you’re in a deficit.

On body comp: intermittent fasting didn’t cost me muscle; if anything, it helped. But can someone do low-fat, high-protein keto and rely on body fat for the rest?

Not indefinitely. I’ve used short protein-and-veg days with lower fat to drop body fat fast, then returned to keto; big protein bumps are anti-ketogenic, so I time them after heavy training to aid recovery, then slip back into higher ketones.

For neurodegeneration risk and prevention, can periodic keto help delay onset?

We don’t have a definitive answer, but targeting insulin, hsCRP, glucose, A1C, omega-3 status, B12, and magnesium—and training, body comp, and VO2—strongly supports brain health. Metabolic health tracks closely with brain health.

Given my lipid quirks, I don’t want to live in keto year-round. What’s the minimum effective dose for cognitive and anti-inflammatory carryover if I keep a low-carb Mediterranean approach most of the time?

You can get most benefits on low carb and cycle deeper ketosis periodically; more is not better. One to two millimolars is the sweet spot for many goals; use CGMs for personal diet feedback, keep moving, build muscle, and track progress with DEXA.

For cadence, is one week per month better than a three-week block once a quarter?

Both can work; pick what fits your life. For the one-week block, consider the first two days at roughly half calories to ramp ketones quickly, and prep your environment so compliance is easy.

If your family history is gnarly, would you personally lean toward the one-week-per-month approach?

I aim for a glucose–ketone index around one to two for three days each week, treating it like a therapeutic block so the signaling and fat–ketone adaptation carry benefits for weeks.

For folks doing the math, you convert glucose to millimolars and divide by ketones; what do practical targets look like on a meter?

Something like glucose around eighty milligrams per deciliter with ketones near two millimolars lands you in that zone, and pushing glucose toward the high sixties with ketones near three gets you close to one, which is tough but doable with smart support.

My readings are oddly low even when I feel very ketotic; is there any way to account for higher ketone uptake so I can still hit the target range?

One to two is a high bar, and I view one to four as therapeutically solid, especially since one millimolar can fuel a meaningful slice of brain energy and improve blood flow; meters only see D‑beta‑hydroxybutyrate, while racemic products also deliver the L form that clears slower and may aid vascular function.

Given the way I feel and how consistently I’m eating, I may just stick with the protocol even if the numbers stay modest.

Track performance too—weights, reaction time, and app‑based cognition—and compare your baseline in and out of ketosis so you have functional biomarkers, not just blood drops.

I’ve got cognitive testing scheduled, zone two feels easier, and my visual‑processing training keeps getting faster; how should everyday users think about exogenous ketones, good and bad?

Judge them by taste, tolerance, time course, and safety, because fast‑rising esters can spike insulin, shut off your own ketone production, and leave you in an energy dip unless you buffer with MCT or food.

Let’s focus on supplement use toxicity for laypeople.

I’m cautious with one‑three‑butanediol and BD‑based esters since they run through alcohol dehydrogenase, drain NAD, stress the liver, and in daily use have shown concerning changes; monoester is roughly half BD and diester about a third, which makes chronic dosing a red flag.

Do you think that risk translates to humans, and at what kind of dose?

Long‑term human data are thin, but when I held two millimolars with roughly thirty milliliters three times a day for two weeks, my AST, ALT, and GGT climbed, and animal histology shows liver issues even when enzymes look normal, so the field is moving toward non‑BD chemistries and better blends.

I’ve tried diester, monoester, and salts; small monoester doses feel good but bigger ones crash me, so how risky is a low dose with MCT?

For healthy livers, small amounts are likely low risk, but I’d cap BD‑based esters around twenty milliliters per day and skip some days, and consider well‑designed salts with both D and L or free‑acid options to get similar ketosis with fewer downsides.

How exactly does MCT help?

It slows absorption while nudging your liver to make its own ketones, but very high intakes can inflame the liver in models at human‑equivalent intakes near eighty to one hundred milliliters a day.

What’s a reasonable ceiling for MCT?

About twenty milliliters once or twice daily with meals works for many, and empty‑stomach dosing often backfires.

Could exogenous ketones in the morning blunt my own production, like hormone replacement does?

We mainly see that with BD and BD‑esters because the insulin spike suppresses endogenous ketogenesis, whereas salts taken to similar levels don’t show that effect.

I only use monoester sporadically before training.

A protein‑heavy breakfast with fat can lift daytime metabolism and curb late overeating if it doesn’t dull your focus, and remember BD behaves like alcohol with dependence and withdrawal documented.

I’ve felt that intoxication firsthand with an alcohol‑alternative drink, and it was not subtle.

That sedation is real, driven by GABAergic effects, which is why I warn older folks with lower detox capacity and fall risk; I deeply credit Richard Veach’s early ester work, but I’ve pivoted away from BD‑heavy tools as the data matured.

Switching gears, what are your go‑to fiber sources on keto?

Broccoli florets, wild blueberries, and small apples for pectin are my staples, noting some people get gassy with certain fibers.

Emphasis on truly wild berries, not the giant dessert fruit.

You can find large frozen bags of wild mixed berries at common supermarkets.

How much fruit fits without derailing ketosis, especially with nuts adding hidden carbs?

My daily mix of walnuts, small apples, wild blueberries, and broccoli totals roughly sixty to seventy grams of carbs with about a third as fiber, eaten later in the day while I sit around half to one and a half millimolars at six feet and two hundred twenty pounds, and re‑adding some carbs plus lifting helped me regain lean mass after strict keto.

Got it, and I’ll note you’re dealing with a strange gummy incident that left you dizzy.

We both took a supposedly calming gummy and felt off for days, so I’m doing forensic labs to see what was in it.

Yeah, it’s scary. My wife doesn’t drink or use anything, so she was shocked, and we both did urine collection, I lined up blood work, and a forensic lab with doctors is now involved because this could have ended very badly for someone fragile.

Same here—I only took two, and I’m a big guy, but imagine a kid taking a few; it feels like the seller messed up the batch or loaded it with something, maybe super high THC. I’m still feeling it nearly two days later, waiting on labs, so please be careful out there.

People need to be careful. Dom, anything else you want to share before we wrap?

Quick shoutout to Dr. Annette Bosworth—she took the sardine fasting idea, put it to work, and amplified it to a huge audience, and the feedback I got from her community really reinforced the benefits. She’s been spreading it on big shows too.

There’s a path where you start premium, fund the R and D, then scale to a broader, more affordable offering; I’d happily pay for convenience because I’ve hit my limit on canned fish and ribeye, so I’ll check out Many Foods. Are you active anywhere folks can follow you?

I keep social light—maybe an hour a week, sometimes deleting apps—but I try to respond and gather questions. We have The Metabolic Link podcast and the Metabolic Initiative platform with ACCME accreditation for CME, aimed at moving all this into real‑world use.

Any other links you want to mention? We’ll add them to the show notes.

ketonutrition.org—no products, just information—plus The Metabolic Link podcast and the Metabolic Health Initiative education platform are the main ones.

We’ll link everything at Tim.blogslash podcast—just search Dominic for the latest. Thanks for making the time, and thanks to everyone listening; until next time, try being a little kinder to others and to yourself, even if you’re beating yourself up about missing your GKI targets like I do sometimes.

One more thing—Five Bullet Friday is my short weekly email with fun finds from the week, like articles, books, albums, gadgets, and odd tech tricks from friends and guests that I test and share. If you want in, go to tim.blogslashfriday, drop your email, and you’ll get the next one.