Can Being on a Keto Diet Put you at Risk for a False DWI?

By the Criminal Defense Attorneys at Knox Law Center in Charlotte & Lake Norman

It’s the stuff of nightmares: you’re driving and the police pull you over to administer a Breathalyzer test. You’re confident you’ll pass–you haven’t had a drop of alcohol all day. To your shock, however, the test indicates your Blood Alcohol Content (BAC) is above the legal limit. The next thing you know, you’re under arrest for Drinking While Intoxicated (DWI).

For some people on the ketogenic diet, this scenario has become reality[1]: being on this diet may cause a false reading on the Breathalyzer, getting you into trouble. Let’s take a look at why this happens, and what to do if this scenario happens to you.

How can the ketogenic diet cause a false positive?

The ketogenic diet is a high-fat, very low-carb diet that helps you burn fat more effectively. As the body begins to burn fat for energy instead of glucose, it produces “ketones,” a form of acetone. Ketones circulate in your bloodstream, but when excess ketones are released through the breath, they have a chemical composition to isopropyl alcohol.

Unfortunately, some older models of breathalyzers[2] can’t distinguish between ethanol-based alcohol (e.g., beer or liquor) and isopropyl (e.g., rubbing alcohol), and will indicate a high BAC.  And then you’ve got a problem.

What should I do if I think I got a false positive?

If you get arrested for DWI in Charlotte, North Carolina but haven’t been drinking alcohol, you should do three things.

  1. Stay Calm. While you may be surprised at the false positive, it’s essential to remain calm and polite. Being in ketosis can produce fruity-smelling breath reminiscent of alcohol, so shouting angrily or otherwise acting alcohol-impaired will not make the police officer inclined to listen to or believe you.
  2. Ask for a blood test. Explain the situation to the police officer and request a blood test (if you haven’t been drinking) that will show that the absence of ethanol in your body.
  3. Call a Charlotte DWI lawyer. An experienced DWI lawyer has seen situations like this before and can help manage the situation.

At Knox Law Center, our skilled DWI lawyers are experienced at helping drivers falsely arrested for DWI.  If you believe you’ve been wrongly charged with a DWI in the Charlotte area, please contact us today.

[1] https://www.menshealth.com/health/a26063314/ketosis-breathalyzer-alcohol-false-positive-low-carb/

[2] https://www.health.com/weight-loss/new-keto-breathalyzer


The attorneys at Knox Law Center have been providing effective criminal defense services for decades in Mecklenburg & Lincoln county, including greater Charlotte, NC. Our attorneys can help navigate the confusing and expensive process of clearing charges from individual’s records, reinstating their full rights and generally helping to put DWI criminal charges behind them. Give our Charlotte DWI criminal defense lawyers a call today to learn more about your options.

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