Ketosis on fast food is possible if you strip the bun and keep carbs low enough, but the patty itself isn't what decides it. The film shows Dr. Mike testing blood ketones with a handheld meter during the 30-day burger experiment, and in my experience the bread, sauce and sides are almost always the real variable people forget to control.
Can you get ketosis on fast food?
Ketosis on fast food is not about the burger. It’s about what’s wrapped around it. Dr. Mike’s protocol was 20 Burger King patties a day, no bun, no seasoning, water only, for 30 days — the film shows that exact rule stated on camera. Strip the bun, and a plain beef patty carries almost no carbohydrate. Keep the bun, and you’ve added sugar back into a meal that would otherwise sit near zero.
What did the blood ketone readings actually show?
The film shows blood ketone testing with a handheld meter at multiple points, not just a single number. Jim’s own on-camera experiment measured a baseline of 0.1 mmol/L, then a rise of 0.7 mmol/L about two-and-a-half hours after 12 grams of exogenous ketones (in the film at 01:29:05 and 01:34:56). The highest reading Jim got that day was 1.1 mmol/L (in the film at 01:30:12). None of these are the burger-only numbers — they’re separate tests the film uses to teach what the meter measures and how fast a number can move.
If you aren't testing, you're guessing. The bun decides more than the patty ever will.
What decides ketosis on fast food: the bun or the patty?
The film suggests the bun, not the patty, is the deciding factor. A typical fast-food bun carries up to 9 grams of sugar according to the book, and on camera one bun specifically is called out at 10 grams of sugar. Twenty patties a day with that bun removed keeps daily carbohydrate near zero; leave the bun on twenty times a day and you’ve added a meaningful daily carb load back in. That’s the whole swing between staying in ketosis and not, and it has nothing to do with the meat.
You can read more about what removing the bun changed in the body in Bunless burgers and insulin: what ditching bread changed.
What does the evidence say about carbs, protein and gluconeogenesis?
The evidence says nutritional ketosis is typically defined around a very-low-carbohydrate ceiling — the meta-analysis by Bueno et al. (2013) defines ketogenic diets as 50 grams of carbs a day or less, and finds that threshold produces slightly greater long-term weight loss and lower triglycerides than a low-fat diet. Whether high protein intake blunts ketosis through gluconeogenesis is a common worry, but the film doesn’t run a controlled protein-titration test, so I won’t claim a number here that isn’t in the film or the studies.
On exogenous ketones specifically, the evidence says a ketone ester drink can raise blood beta-hydroxybutyrate to 2.8–3.5 mM within an hour, per Stubbs et al. (2017), while ketone salts raise it less and add a sodium load — which lines up with why Jim’s on-camera rise from a ketone salt-style dose was smaller than an ester would produce. In starvation physiology, Cahill (2006) describes the brain shifting largely to beta-hydroxybutyrate during prolonged fasting — a different scenario than eating patties daily, but useful background for what the meter is actually tracking.
How do you test for ketosis: blood, urine or breath?
The film only shows blood testing with a handheld meter — that’s the method used for every ketone reading in the 30-day protocol and in the fasting phase. In my experience with clients, urine strips are the cheapest way to get a rough yes/no answer early on, but they measure excreted ketone bodies, not what’s circulating in blood, and they get less reliable once someone is fat-adapted and excreting less. Breath meters exist too, and the book describes a breath-hold test alongside blood ketones in Jim’s own experiment, though breath-hold time is a proxy for tolerance, not a ketone concentration. If you want an actual number you can compare over time, blood is what the film uses and what I’d use.
What does a ketone number tell you — and what doesn't it tell you?
A single blood ketone reading tells you where you are at that moment, nothing more. The film states a standard range of roughly 0.5 to 3.0 mmol/L for what’s typically called nutritional ketosis on camera — that’s the number the crew uses to explain a reading, not a verdict on health. The film suggests one reading, taken once, says little about the following week; Dr. Mike’s own numbers moved around across the 30 days depending on what he’d eaten, how much water he’d had, and how he’d slept.
What it doesn’t tell you: whether you’re losing fat, whether your lipids are moving, or how your body is handling 600 burgers over a month. That side of the story is covered separately in 600 Burgers in 30 Days: What Happened to Dr. Mike’s Blood, and I’m not going to give away the final numbers here.
Should you eat only fast-food patties to reach ketosis?
In my experience, testing this with clients, the pattern that matters is simpler than the food source: strip added sugar and starch, keep total carbs low, and the ketone number usually follows within days, whether the protein came from a fast-food counter or a home kitchen. Dr. Mike’s own on-camera macro estimate for the 20-patty protocol — 180 grams of protein and 700 milligrams of cholesterol a day, by his own calculation, not a lab assay — shows how much can shift when you’re eating that much of one food, which is a separate conversation from whether it’s ketogenic. Individual results vary, and this isn’t medical advice; it’s what got measured on camera and what I’ve seen testing people off camera. If you want the electrolyte side of what changes in week one, that’s covered in Why Electrolytes on Keto Matter More Than Fat in Week One.
Frequently asked questions
Can you stay in ketosis eating only fast-food burger patties?
A plain beef patty without a bun carries almost no carbohydrate, so it doesn't block ketosis on its own — it's the bun, sauce and sides that typically do. Individual results vary.
What blood ketone level counts as nutritional ketosis?
The film states a range of roughly 0.5 to 3.0 mmol/L as the standard for nutritional ketosis on camera.
Is a blood ketone meter better than urine strips?
Blood meters measure what's circulating and are what the film uses throughout; urine strips are cheaper but measure excreted ketones and get less reliable over time, in my experience.
Does eating a lot of protein stop ketosis through gluconeogenesis?
The film doesn't run a controlled protein test to answer this directly, so no specific figure from the experiment applies to that question.
Does the film give Dr. Mike's final ketone or lab results?
No — those results are the film's ending and aren't published here; you'd need to watch the film for that.
The Bottom Line
Ketosis on fast food comes down to what you leave out, not what you order. Strip the bun, watch total carbs, and test blood if you want a real number instead of a guess — that’s the same approach the film uses throughout the 30-day protocol. What happened to Dr. Mike’s own numbers over the full 30 days, and where they landed, is worth watching rather than reading in a summary.
Watch The Keto Project and read 600 Burgers in 30 Days to see the full testing protocol and follow the numbers yourself.
Sources
This article is for information only and is not medical advice. Individual results vary. Speak to a qualified clinician before changing how you eat.
The whole experiment is in the film. 600 burgers, 30 days, every blood test — and the ending we never post.
Watch The Keto Project on Amazon