Can Your Diet Affect Your DUI?

David Lindsey, Attorney at Law
ketosis defense

Ketosis Defense

Embracing a low-carb diet might result in weight loss and feeling healthier, but it could also get you arrested.

It might sound crazy but it’s true. A low-carb diet can trick a breathalyzer test into producing false results.

Breath tests or breathalyzer tests are administered at the scene of a traffic stop when law enforcement suspects someone of driving under the influence of alcohol. The test measures (often inaccurately) your blood alcohol concentration (BAC). It’s no secret that these tests have a lot of problems, which include producing false results based on various factors. One of the most common problems in recent years especially has been elevated results based on someone’s diet.

DUI Test Results and Ketosis

How can what you eat affect your breathalyzer test results?

To understand how your breathalyzer test results can be falsely elevated based on what you eat, it’s important to understand ketosis.

Ketosis is the condition that occurs when your body turns to its storage of fat because you reduce the amount of carbohydrates you consume. When this occurs, your body produces ketones. Ketones are chemically similar to isopropyl alcohol – which is where the problem with the breathalyzer test comes in. The test checks for alcohol in the blood, but it can’t tell the difference between different alcohols. This means your BAC level could be higher than it is if the test picks up on the ketones in your system.

You could be completely sober and still register as intoxicated on a breathalyzer test.

Symptoms of Ketosis

Breathalyzer test results aren’t the only problem you face when eating a low-carb diet. People who are in ketosis experience many of the same symptoms as someone who has been drinking alcohol. This includes:

  • Headache
  • Brain fog
  • Fatigue
  • Nausea
  • Bad breath
  • Impaired physical ability

Essentially, someone in ketosis could be mistaken as drunk.

Who is affected by falsely elevated BAC results due to ketosis?

Anyone who has lightened their carb intake enough to trigger ketosis is at risk for a false positive on their breathalyzer test results. But most often, this problem for people with diabetes, both type 1 and type 2, and people adhering to a low-carb diet.

This includes Atkins, paleo, and more.

These things don’t guarantee ketosis, but they increase your likelihood. As a matter of fact, some dieters even make ketosis a goal because they know their bodies are burning stored fat, which helps them lose weight.

Unfortunately, without testing the ketones in your urine, you won’t know that you are in ketosis. But if you’re low on carb intake and your BAC test shows an elevated level of alcohol, despite not having any drinks, chances are you are.

Using Ketosis as a Defense

It might seem as if using ketosis as a defense against DUI charges would be an easy way out of your situation, but this isn’t the case. The court will require some proof to back up your defense. But what qualifies as proof of ketosis if you didn’t take a ketone urine test at the same time your breathalyzer test was administered?

Other evidence that can be used to support your claim of ketosis includes:

  • An official medical diagnosis of diabetes
  • Medical proof of your low-carbohydrate diet
  • Receipts showing what you consumed at your last meal(s)
  • Statements from people familiar with your dieting habits
  • Personal food journal

The medically backed evidence is stronger than the other things on the list, but you could still make a decent argument using any of the above.

What If I Was Drinking?

Can you still use ketosis as a defense against DUI charges if you did have an alcoholic drink or two?


Even with a drink or two, your BAC could still be under the legal limit (usually .08% depending on where you live). But ketones could make it look like you’re over the legal limit. In this case, you’ll use the same defense as you would have had you consumed no alcoholic drinks. The only difference is there were some traces of liquor in your system.

Ketosis has been used more in recent years since low-carb diets have become a legitimate approach to weight loss. If you believe ketosis affected your breathalyzer test results or you want to speak to someone about a drunk driving arrest, David Lindsey can help. Contact him at 303.228.2270 to schedule a free consultation.

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