The keto diet is all the rage these days. It was the most searched diet on Google in 2018. It is a low carb way of eating, similar to the Atkins diet that was popular in the early 2000s. But what many eating keto may not realize, is that it can actually cause a false positive on a breathalyzer test.
What is keto?
The goal with keto is to eat in a way that puts your body into continual ketosis. In order to do this, you need to eat around 20 grams of carbohydrates per day. This is significantly lower than the around 300 most people eat.
With such a low level of carbs, the body turns to glycogen – which is stored in the liver – for energy. This causes the liver to produce ketones. When this happens, a person is in ketosis and the body burns fat instead of holding on to it.
How can keto trigger a breath test?
When the liver breaks down the fat, it produces a byproduct called acetone. You release this acetone through your breath as isopropyl alcohol. This can in turn trigger some breathalyzer tests.
However, do not read this to think that saying you eat keto is a way to get out of a drunk driving arrest or charge.
Police use high quality fuel cell breathalyzer tests. So, while a more inexpensive breath test – like the ones people buy to test their own blood alcohol content at home — may not necessarily be able to tell the difference between isopropyl alcohol and ethanol alcohol, the tests police use should be able to make that distinction.
But what about cases where someone has consumed alcohol and is following the keto diet?
According to at least one source, there is no peer reviewed data showing how the breath tests differentiate between the two types of alcohol: isopropyl and ethanol. Not having this data holds the door open for questioning, which can be important in defending against alcohol related driving charges, including DUI.
Can being keto get you out of a DUI?
Simply saying that you are following the keto diet is not going to be enough to get you out of a DUI. You can certainly tell the officer this, but you will most likely still wind up in the back of a squad car. You are going to need more on your side to defend against a DUI.
Drivers should also keep in mind that it’s not just the chemical test that matters in DUI cases. You can be charged with DUI or DWAI based on your driving, the police’s observations of your demeanor and coordination, your performance on voluntary roadside maneuvers, and other similar factors.
It’s important to remember that the observations and claims made by the police are not the end of the story. Just as a lawyer can legally challenge the results of a breath test, it is also possible to challenge the allegations claims made by a police officer.