How Low-Carbohydrate / High-Protein Diets, Diabetes, and Hypoglycemia can "Trick" a California DUI Breath Test

There are a variety of physical conditions...some that are self-imposed such as high-protein / low-carbohydrate diets and others that are beyond our control such as diabetes or hypoglycemia...that can adversely affect a California DUI chemical breath test.

This is because these conditions produce "ketones" which cause the body to create isopropyl alcohol. When a person blows isopropyl alcohol into most DUI breath testing instruments, it typically gets mistaken for ethyl alcohol (the type of alcohol that we consume in an alcoholic beverage). As a result, innocent people are often falsely accused of (and arrested for) California Vehicle Code 23152b driving with a BAC of 0.08% or greater.


  1. you were on a low-carbohydrate / high-protein diet like the Atkins diet, and/or
  2. suffer from diabetes or hypoglycemia, and
  3. submitted to a California DUI chemical breath test,

it is critical that you contact a California DUI defense attorney to explore this often overlooked yet very effective California DUI defense.

Low-carbohydrate / high-protein Atkins-style diets can affect blood alcohol concentration levels during a California DUI breath test

When people eliminate or significantly reduce their carbohydrate intake, their bodies look to stored fat for energy. When this phenomenon takes place, ketones are produced, which is what the body relies on for that energy.

The problem (with respect to ketones and DUIs) is that certain ketones can't be used by the body, because they convert to isopropyl alcohol. As a result, these types of ketones are excreted by the body in urine and breath.

When excreted in the breath, isopropyl alcohol is no different from ethyl alcohol (which is the type of alcohol that we drink). This means that someone whose body is in "ketosis" (which is the process of producing isopropyl alcohol) can fool a California DUI chemical breath testing instrument.1

This is because DUI breath testing instruments are not sophisticated enough to distinguish between isopropyl and ethyl alcohol.2 So someone whose body is auto-generating isopropyl alcohol will produce a blood alcohol concentration (BAC) just as if he/she were drinking alcohol.

And if an individual on a low-carb Atkins-style diet actually consumed even a small amount of alcohol, his/her BAC would be falsely elevated simply because of the ketones naturally produced in his/her body.3

Another interesting fact to note is that...when excreted in the breath...ketones cause a foul odor. The breath of an individual who is on a low-carb diet...and therefore excreting ketones in his breath...can smell very similar to someone who's been drinking alcohol. This is one of the reasons that an officer may mistakenly suspect that someone who has simply been on an Atkins-style diet is, in fact, driving under the influence.

Similarly, diabetes and hypoglycemia can trick a DUI breath test into producing falsely high BAC levels

Ketones are not unique to Atkins-style diets. A person's body also produces these if he/she suffers from diabetes and hypoglycemia. Both of these medical conditions can send the body into ketosis. When carbohydrates are introduced into one's system during ketosis, the result is the production of isopropyl alcohol.

And, as stated above, most California DUI breath testing instruments aren't technologically advanced enough to distinguish between isopropyl and ethyl alcohol. This means that those who are diabetic or hypoglycemic will also produce a false illegal BAC despite the fact that they may have consumed little or even no alcohol.

If a diabetic or hypoglycemic individual enters the state of "ketoacidosis", he/she may also exhibit signs and symptoms of intoxication

When too many ketones are produced in a diabetic's body, it can ultimately lead to a serious condition called "ketoacidosis".4 When the symptoms of diabetic ketoacidosis appear, they can mimic the signs of alcohol and/or drug impairment. These symptoms include (but are not limited to):

  • flushed face,
  • drowsiness,
  • loss of energy,
  • impaired coordination, and
  • stale breath which, as previously stated, can be mistaken for the odor of an alcoholic beverage.5

These symptoms... when they cause a driver to fail a DUI breath test...unfortunately lead to a great number of false DUI arrests and wrongful DUI prosecutions.

As police become more aware of how these medical conditions and diet restrictions can duplicate impairment, perhaps less innocent people will face wrongful DUI charges. Until then, make sure that you tell your California DUI defense attorney if any of these situations may explain your unjust drunk driving charges.

As the well-known Orange County DUI defense lawyer John Murray explains6, "It's my job to make the jury understand that things aren't always what they seem...especially when it comes to a California driving under the influence case. Just because my client had a BAC over the legal limit and what the officer believed was the smell of an alcoholic beverage emitting from his breath does not mean he was DUI...particularly when his diabetes, hypoglycemia, or Atkins-style diet prove otherwise."

If you have additional questions about how low-carb / high-proteins could adversely affect your BAC, or you would like to discuss your case confidentially with one of our California DUI defense attorneys, please don't hesitate to contact us. We have local DUI law offices in Los Angeles, Riverside, Orange County, San Bernardino, Ventura, San Jose, the San Francisco Bay area, and several nearby cities.

You may also find helpful information in our related articles on Vehicle Code 23152b Driving with a BAC of 0.08% or Greater, Blood Alcohol Concentration and California DUI laws, California Chemical DUI Breath Tests, and California DUI Defenses.

Call us for help

If you or loved one is charged with a DUI and suffer from ketosis and you are looking to hire an attorney for representation, we invite you to contact us at Shouse Law Group. We can provide a free consultation in office or by phone. We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California.

Legal References:

1Lawrence Taylor "Drunk Driving Defense" 3d Edition, page 685. ([with respect to low-carbohydrate / high-protein diets] "...the likelihood exists of auto-generated isopropyl alcohol upon the introduction of carbohydrates in the presence of ketosis and that the [California DUI breath testing instrument the] Intoxilyzer cannot dependably distinguish ethanol from isopropyl alcohol.")

2See same. ("As noted before, isopropyl alcohol is virtually indistinguishable from ethanol in the infrared test chamber of the five-filter Intoxilyzer [California DUI breath testing instrument]. Because the isopropyl alcohol is coming from end expiratory air, as is the ethanol, there is little possibility of triggering the negative slope detector and reporting 'invalid sample.' Most breath test devices will render a cumulative reading of ALL alcohols in the body (ingested and auto-generated) [which can lead to false California DUI arrests due to an Atkins-style diet].")

3This was the scenario in a Georgia DUI case entitled People v. Redstrom. Redstrom had been on a strict low-carbohydrate / high-protein diet when he had four beers over a five hour period and was finished drinking over two and one-half hours prior to his DUI investigation. Because of the fact that his body was in ketosis when he reintroduced carbohydrates (that is, beer) back into his system, his DUI breath test reported a falsely high BAC.

4American Diabetes Association "Living with Diabetes" Ketoacidosis website. [With respect to diabetes and DUI] "High levels of ketones can poison the body. When levels get too high, you can develop diabetic ketoacidosis, or DKA [the symptoms of which mimic alcohol and/or drug intoxication]."

5See Taylor's "Drunk Driving Defense" endnote 1, above, page 682. ("Perhaps gradually and over a period of days, the symptoms of diabetic ketoacidosis appear: drowsiness, flushed face, thirst and loss of energy and appetite...the client's physiological condition may be emulating the outward signs of intoxication to a police officer: lethargy, flushed face, drowsiness, impaired coordination, dulled mental alertness.") See also page 683. ("Further, the acetone on the breath from ketoacidosis will result in an odor of alcohol.")

6Orange County DUI defense lawyer John Murray has an outstanding success record for defending California DUI clients in Los Angeles, the South Bay, and Orange County. We invite you to contact us to learn more about his impressive resume and service areas.

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