Continuous Ketone Monitor Cleared: What Spot Checks Missed

The first continuous ketone monitor cleared in the United States is Abbott's Libre Duo 10 Day, authorized by the FDA on 25 August 2026 for people aged two and older with diabetes, and it exists to flag rising ketones before diabetic ketoacidosis — not to grade a keto diet. Our 30-day burger experiment ran on scheduled draws and finger sticks. The overnight hours and the post-meal windows? Never sampled. That one is on me. Here is the test you can actually run at home.

What is the first continuous ketone monitor the FDA cleared, and what is it for?

It is Abbott’s Libre Duo 10 Day, and the FDA authorized it on 25 August 2026 for people aged two years and older living with diabetes — the first wearable in the United States to continuously track ketones, and the first anywhere to track ketones and glucose in one sensor.

Here is what the device does. It measures glucose and ketone levels in the fluid just beneath the skin every minute, day and night, sends readings to a phone, and can alarm when ketones reach a concerning threshold. Six clinical studies enrolling more than 600 participants were reviewed by the agency’s Center for Devices and Radiological Health through the De Novo pathway, the route used when an innovative measurement has no existing category.

So the purpose is narrow. It is medical. It catches rising ketones before diabetic ketoacidosis turns into an ambulance ride. That is the whole job. Abbott’s release puts it in a line from Chris Scoggins — “If glucose is the speedometer, ketones are like the check engine light” (Abbott).

Is a continuous ketone monitor a green light for the keto diet?

No. The authorized use is diabetes care, not diet scoring: Abbott says the system is for people at higher risk of elevated ketones, including those with type 1 or type 2 diabetes using insulin or drugs such as SGLT2 inhibitors.

Ketoacidosis and nutritional ketosis are not one event at two volumes. One is insulin failure. The other is a fuel switch in someone whose insulin still works. I say it on camera, meter in hand, sounding more certain than I felt: nutritional ketosis lives between 0.5 and 3.0 millimoles per liter of blood (The Keto Project), well below the territory this device was built to catch, and the labelling is honest: Abbott warns the Urgent High Ketones alarm may not detect every event and that ketone output should be used with glucose levels, the gap stated as ketones above 3.0 mmol/L.

So read it as what it is. A safety tool for patients, cleared on accuracy and performance data. Not a gold star for your dinner. Individual results vary. No sensor on earth changes that.

What did we actually measure across the 30 days of 600 burgers?

Blood draws. Finger sticks. Physical testing, over and over. All of it at fixed points. None of it continuous. The book lists the panels: hormone and cardiometabolic markers plus liver, thyroid, kidney and inflammatory panels, across four test points.

Dr. Mike ate 20 Burger King patties a day for 30 days, no bun, water only, 140 patties to the weekly order; the film shows a Fitbit averaging his expenditure at 2,723 kcal a day, and Chantea Goetz running a session where his heart rate moved from about 70 to below 50 during ten minutes of paced breathing (The Keto Project). The evidence says a wrist is a rough instrument: a meta-analysis of Fitbit sleep accuracy found sensitivity near 0.95 but specificity near 0.6.

That is the shape of most self-experiments. Ours included. Good instruments, sampled too rarely. I wrote the schedule, so you know who to blame.

What would a continuous ketone trace have caught that our spot checks missed?

Three things the journal points straight at. The overnight hours. The window right after a meal. The long gaps without food. We sampled none of them.

The film shows Dr. Mike describing discomfort for about 10 minutes to 3 hours after eating, and dizziness on standing that appeared on Day 6 and returned repeatedly a week later (The Keto Project). The book has him writing on Day 27 that eating made him feel sick and 12 or more hours without food was when he felt best (600 Burgers in 30 Days). The film suggests — interpretation, not measurement — a repeating post-meal trough and an overnight climb, the shape a minute-by-minute trace draws and a morning draw cannot.

The evidence says those early symptoms stay under-measured: an analysis of 60 online reports described headache, fatigue, nausea, dizziness and brain fog clustering in the first week — self-reported, no labs attached. Nobody holding the curve.

Can glucose and ketones move in opposite directions on the same day?

Yes, and that is the best reason to watch both numbers rather than one.

In the book, Dr. Dom D’Agostino explains that glucose does not really fall below about three millimolar, and that with glucose at three and ketones at three the brain runs as a hybrid system (600 Burgers in 30 Days). The evidence says supplements pull the two apart on purpose: crossover studies in 15 to 16 healthy adults found ketone ester drinks raised blood beta-hydroxybutyrate to 2.8 to 3.5 mM within an hour, salts about 1 mM, and both lowered glucose.

Then there is my version, n of one, and it is a humbling little piece of film: ketones manipulated down to 0.1 mmol/L, 12 grams of exogenous ketones, a two-and-a-half-hour wait, a rise of 0.7, a ceiling of 1.1 — and my own line that the supplement did no more than not eating all day did (The Keto Project). The book logs the stopwatch half: a 64-second breath hold at baseline, 80 after the dose, 36 hours of gastric distress as the receipt (600 Burgers in 30 Days).

What should I measure at home, and how often?

Use blood beta-hydroxybutyrate as your reference number. Pair every reading with glucose from the same sitting. Then take fewer readings, at better times.

Blood is the reference for a reason. An NIH-hosted review of ketone measurement notes that beta-hydroxybutyrate is the main ketoacid in blood while urine strips measure acetoacetate, so urine can read higher even as ketosis resolves, making blood beta-hydroxybutyrate the preferred test. The film shows that in practice: my urine strip read moderate, then small after a quarter to half a gallon of water (The Keto Project).

• Morning, fasted: one ketone reading, one glucose reading, before coffee and training.
• Two to three hours after your largest meal: the same pair, same meter.
• Weekly: keep the log, not only the current number.
• Quarterly: real labs — see what we drew across the 600 burgers.

Two weeks of paired readings taught me more than a year of lonely daily numbers ever did. And which diet you are testing decides what they mean.

Frequently asked questions

A breath meter is convenient, but it is a proxy. It reads acetone, formed downstream, while the ketone your liver puts into the blood first is beta-hydroxybutyrate. Breath follows a trend well enough, but when a reading has to be right, take blood.

Diabetic ketoacidosis is insulin failure: ketones and glucose climb together and the blood turns acidic, which is an emergency. Nutritional ketosis happens in someone whose insulin still works, so the rise is self-limiting and far smaller. Same molecule, different situation, which is why a device cleared for one is not a tool for the other.

Nothing in the authorization addresses weight. The device was reviewed for accuracy in detecting rising ketones in people with diabetes, not for diet outcomes, and a sensor never changes what you eat. What data does is end the argument with yourself about whether a meal did what you assumed.

No. No such device existed then, so his ketones were read by finger stick alongside scheduled draws and fitness testing. That is why the measurement log matters more than any single reading, and why his final numbers are revealed in the film rather than summarized in a post.

Test both, from the same sitting. A ketone number alone cannot separate a fat-adapted morning from a dehydrated one or a long fast, and glucose supplies the missing context. Paired readings also keep your log comparable week to week, which is the point of measuring anything.

The Bottom Line

A continuous ketone monitor is now a real, cleared medical device, and that is good news for the patients it was built for. It is not permission. It is not a verdict on your dinner. And it points right at the thing this film was built on: a number taken once a week is a snapshot, and a body lives in the gaps between the snapshots.

We make the keto science, the recipes and the film at Functionised Productions LLC, 8 Merchants Way, Colts Neck Township, New Jersey, 07722. For the full measurement log — every panel, every test point, and what Dr. Mike’s bloodwork did by the end — rent or buy The Keto Project or pick up 600 Burgers in 30 Days.

Sources

• FDA Authorizes First Wearable Device That Continuously Monitors Both Ketone Levels and Blood Sugar
• Abbott receives FDA authorization for world's first dual glucose-ketone sensing technology
• Libre DUO 10: Dual Glucose and Ketone Monitoring (Abbott, important safety information)
• FDA Clears First Continuous Glucose-Ketone Monitor (Pharmacy Times)
• Update on Measuring Ketones (NIH, PMC)
• Accuracy of Wristband Fitbit Models in Assessing Sleep: Systematic Review and Meta-Analysis
• Consumer Reports of Keto Flu Associated With the Ketogenic Diet
• On the Metabolism of Exogenous Ketones in Humans