Day 20 Keto Project: Why He Kept Eating Anyway

Day 20 of The Keto Project was a short, ugly entry: Dr. Mike woke with nausea, a headache and a stomachache, then got an unusual burst of energy at midday, two-thirds of the way through eating 600 burgers in 30 days. Nothing dramatic happened and that is the point — by week three the symptoms were no longer events, they were the background of every meal, and finishing had stopped being a certainty. Here is what the day 20 keto project journal and the film actually record, and why he kept eating instead of stopping.

What does the day 20 Keto Project journal entry actually say?

The day 20 keto project entry lists four things: nausea, a headache, a stomachache, and an odd burst of energy at midday. That is the whole entry. The day 20 keto project record is shorter than the days on either side of it. By week three, a day like that no longer felt notable enough to write up.

A bag of plain patties. A jug of water. No bun, no ketchup, no choices left at any meal. The film shows the rule in his own words, “I’m eating just Burger King burger patties and drinking water and that’s it. No seasonings. No flavorings. Nothing else for 30 days” — twenty patties a day, thirty days, six hundred patties, as the film lays it out from Day 1.

Here is the real problem with a short entry. It reads like a quiet day until you put it between its neighbours. On Day 19 he woke energized and then could not get air in his workout. On Day 21 he had a headache for six hours and four people in an hour told him he looked like an albino zombie, as he logged it in the book.

Why did finishing the 30 days feel uncertain by day 20?

Because nothing was new anymore. The symptoms had stopped arriving as events and settled in as the background of every meal.

What the film shows, on camera and in his own account:

• Discomfort for 10 minutes to 3 hours after every meal, and in his words “it’s only been mildly increasing every day” (the film).
• Looking back, he says he was “puking in my mouth minimum at least once every day after day four” — his words, with no diagnosis made on camera.
• Water pushed up to one and a half to two gallons a day by Day 16.
• Orthostatic dizziness — stand up too fast and the room goes — first logged on Day 6, then several times in one day a week later.

Then the line that makes Day 20 heavier than its own entry. Looking back, the film shows him saying, “I’ve never had a full bout of acute depression, and it certainly came from this.” He is a physician. He volunteered. He was not finished.

Was day 20 keto flu, or was something else going on?

By the published timeline, this was not keto flu. The evidence says the cluster of symptoms people call keto flu belongs to the first week, not the third.

A qualitative analysis of 60 online reports found headache, fatigue, nausea, dizziness, brain fog and gut issues peaking in the first week, mostly mild to moderate and resolving within weeks (Bostock and colleagues, 2020) — forum self-reports, nothing measured. A systematic review of randomised trials also put side effects on ketogenic diets in the early weeks (Abboud and colleagues, 2021). Neither describes a Day 20.

The film suggests the load by then was volume and sameness, not carbohydrate adaptation; he was long past the switch, and on camera I give the window I use, 0.5 to 3.0 millimoles per litre of blood ketones, as the standard range for nutritional ketosis (the film). Individual results vary, and this was one trained physician eating one food under observation.

What did the numbers say around day 20 of the experiment?

Around Day 20 the only things being measured were his nervous system and his wearable. No blood was drawn that day, because the panels were drawn at four test points, not daily.

The film shows Chantea Goetz running a heart-rate-variability check in week three: his heart rate sitting around 70, “It was 72 before”, then back below 50 during ten minutes of guided breathing (the film). Dr. Mike wrote on Day 19 that his HRV had been healthy at baseline and was cut in half a week in — Chantea’s read was blunt, “it means you’re getting sick mike” — and by Day 19 it had crawled a little over halfway back.

The evidence says a randomised crossover pilot in military personnel found two weeks of keto induction left cognition, mood and sleep unchanged while tending to lower heart rate variability (Shaw and colleagues, 2022) — exploratory, by its authors’ own account. His sleep came from a Fitbit, and a meta-analysis found Fitbit wristbands detect sleep with high sensitivity but low specificity (Haghayegh and colleagues, 2019) — a rough estimate, not a sleep lab. The book prints no lab values for him at all; what the panels said is in the film’s bloodwork.

Why did Dr. Mike keep eating instead of stopping at day 20?

Because the data he wanted did not exist yet. Stopping on Day 20 would have left an anecdote with no second half, no final fitness test and no closing blood draw.

Remember whose idea the test subject was. I planned to eat the six hundred patties myself; he insisted on taking it, and I documented it instead. He wrote on Day 1 that “we have been talking about it for over 5 years and these kinds of self experiments excite the hell out of me” (the book). Five years of talk is a heavy thing to walk away from in week three.

He also knew the direction already. At the Day 14 retest his best long jump was an inch shorter than his worst baseline jump of 8 feet 5 inches, and his mile came in about 20 seconds slower (the book). In my experience coaching strength and conditioning for the Toronto Blue Jays and the Tampa Bay Buccaneers, that is the moment most people negotiate with themselves. I had skin in the game in a smaller way: that month I held my breath for 64 seconds at baseline and 80 seconds after 12 grams of exogenous ketone salts, blood ketones at 1.1, and about 36 hours of gastric distress as the price (the book).

What happens after day 20, and where can I see how it resolves?

The back half runs in a straight line: the last Burger King pickup on Day 22, the flat shrug of Day 24, the third fitness test on Day 29, the final blood draw on Day 30. How it resolves is in the film and the book, not in a post.

Day 22 still surprises me. He wrote that a four-mile hike in a 30-pound vest kept his heart rate below 100 and felt good, then he crashed on the couch for two hours, and his lesson was “do not try working out within 2 hours of eating 10 burger king burgers, the outcome is not pretty and is painful” (the book). On Day 26 he was jealous of my turkey burger. I added mustard in front of him.

All of it was made out of Functionised Productions LLC, 8 Merchants Way, Colts Neck Township, New Jersey, 07722 — also where our keto science, metabolic health work and recipes come from.

Frequently asked questions

Water only — no soda, no juice, no coffee for the thirty days. The bun, the condiments and the drink were cut to strip out the sugar: the book notes a typical fast-food bun carries up to 9 grams of sugar (the book), which is most of the carbs in a drive-through meal.

By his own on-camera calculation from label data, about 160 grams of fat a day, 50 grams of it saturated, and about 180 grams of protein (the film). That is his estimate, not a lab assay — every lab we approached refused to analyse the patties or quoted a price we would not pay.

Weight loss was never the outcome we were testing, and the book gives no body-weight numbers at the test points. The one weigh-in it prints is Day 8, when his 3D scan read half a pound up after 32 ounces of water on the commute (the book) — roughly where he started.

It was carnivore in food choices and ketogenic in macros: one food, high fat, high protein, effectively no carbs. A low-carb plan using vegetables, dairy and oils is a different test with different variables, which is why we kept it to one item — compared in keto versus carnivore.

No. The book says plainly that this was done under observation for a film and that readers should not try it themselves. If you want to check your own numbers, get bloodwork before you change how you eat, not after.

The Bottom Line

Day 20 is not the dramatic part of the month. It is the part that decides the month, and it looks like nothing: a man with a headache eating lunch in a parking lot because he said he would. If you aren’t testing, you’re guessing — and he kept eating so there would be something to test.

So watch the thirty days from the inside, with the labs, the scans and the day it nearly came apart, then decide what it means for how you eat. Rent or buy The Keto Project on Prime Video, or start with 600 Burgers in 30 Days, where his journal runs day by day. What will you do with it?

Sources

• Consumer Reports of "Keto Flu" Associated With the Ketogenic Diet – PubMed
• Cognitive, Sleep, and Autonomic Responses to Induction of a Ketogenic Diet in Military Personnel: A Pilot Study – PubMed
• Accuracy of Wristband Fitbit Models in Assessing Sleep: Systematic Review and Meta-Analysis – PubMed
• Effect of Ketogenic Diet on Quality of Life in Adults with Chronic Disease: A Systematic Review of Randomized Controlled Trials – PMC
• Watch The Keto Project | Prime Video