THE RELATIONSHIP BETWEEN THE KETO DIET AND BREATH TEST RESULTS

On behalf of Craig E. Gibbs, Attorney at Law on Thursday, February 21, 2019.

The Keto diet has become quite popular in recent years. Many say that eating a high fat, low carbohydrate diet provides numerous health benefits such as weight loss, reduced blood sugar levels and more. Through this method of eating, your body goes into a state of “ketosis” and begins burning fat instead of glucose.

This may sound like a good thing, and many people have experienced benefits from this diet, but a downside exists as well. If a police officer suspects you of drunk driving during a traffic stop, your diet could get you in trouble.

What happens in ketosis

When your body goes into ketosis, the fats that are the hallmark of the keto diet provide fuel for your body after your liver breaks them down. One of the byproducts of this process is acetone. This creates isopropyl alcohol on your breath.

Breath testing machines should pick up ethanol alcohol on your breath if you ingest enough alcoholic beverages. However, it is possible for those machines to pick up the isopropyl alcohol created by ketosis instead. Not only could the potential inability to differentiate between the two types of alcohol land you in the back of a patrol car, but it could also keep you from starting a vehicle fitted with an ignition interlock device.

More than likely, your diet alone would not result in an arrest for DUI. However, if you have a drink or two, that could be enough to push you over the .08 legal limit here in Louisiana on the side of the road. Upon being tested post-arrest, however, you may be cleared of drunk driving since those machines are much more sensitive and able to differentiate between the two alcohols. Even so, the arrest itself may have already done you damage.

The unreliability of roadside breath tests

It may help to know that most courts do not accept the results of roadside breath tests because false positives are more common than law enforcement agencies would like to admit. Even so, you need to know that you probably would not receive a reading of .08 as a sober, keto diet follower. Of course, officers can arrest people with lower blood alcohol concentrations if other behaviors lead them to suspect impairment. Your dietary choices may not be enough to prevent that from happening.