Can a keto diet upset alcohol testing?

Is it possible to fail alcohol testing because of your diet?

We’re normally writing blogs on defeating the myth that you can beat alcohol testing, using things such as special mouthwashes, chewing gums and sprays. See Can you beat alcohol testing? as an example. But in this blog, we want to examine whether there are things (apart from alcohol!) that can cause you to fail alcohol testing.

Flight attendant says keto diet led to positive alcohol testing

The blog is on the back of an extraordinary article on that focussed on a flight attendant who was reportedly fired by American Airlines because he was accused of drinking on a flight and subsequently failed alcohol testing. While that’s reasonably extraordinary, what makes the story more astonishing is that the flight attendant says he didn’t touch a drop of alcohol and the failed test was due to his keto diet.

In the article, its explained that the low-carb, high fat keto diet does in fact have the potential to cause a false alcohol testing result. That’s because these diets produce ketones, such as acetone and beta-hydroxybutyrate, that can be detected when exhaled.

However, the article highlights that while cheaper, less sophisticated alcohol testing devices may be fooled by these ketones, high quality units aren’t. These high quality units are used by professional alcohol testing companies (such as Integrity Sampling) and police forces around the world.

Are there other ways to have false alcohol testing results?

The article does raise an interesting question. That is, are there other ways to potentially have positive alcohol testing results without drinking alcohol? The simple answer is yes:

  • Perhaps the most common way is through foods. While foods don’t contain alcohol naturally, alcohol is added to some dishes. And while some of this might be burnt off during the cooking process (think sauces, gravies, casseroles and baked goodies that use alcohol) if alcohol is added to dishes that aren’t cooked (such as trifles and mousses) no alcohol is lost during the making of the dish.
  • In addition, foods flamed with alcohol appear to have the alcohol burned off, but some is retained.
  • There are also foods that contain alcohol that you might not expect. For instance, some vanilla and almond extracts, mustards, fruit and black forest cake, vinegars, pates and liqueur chocolates.
  • Drinks that you might not expect to contain alcohol, can also contain small quantities. This includes some kombuchas, energy drinks and ‘alcohol-free’ beers and wines.
  • Mouthwash is another product that many of us use that can contain alcohol, although alcohol-free versions are available.
  • Some medications may also contain alcohol.

The lesson for workplaces

What’s the biggest lesson for workplaces from this blog? There are two main ones that we can think of.

Firstly, don’t use cheap, unsophisticated alcohol testing devices to conduct your alcohol testing and always do follow-up results for positive tests.

Secondly, if someone says they haven’t had a drop of alcohol after they fail workplace alcohol testing, remember that this is possible but highly unlikely. Do the follow up testing and make sure the employee is removed from the workplace so he or she is safe.


Is it possible to fail alcohol testing because of your diet? Credit Colin Brown Photography

By Michael

Michael is the founder of Integrity Sampling and is responsible for overseeing all national operations. He is based at Integrity Sampling's head office in Melbourne and is also responsible for the co-ordination of drug and alcohol testing within Victoria, assisting in the implementation of drug and alcohol (fit for work) policies and the presentation of drug and alcohol education and awareness programs. You can connect with Michael Wheeldon on LinkedIn

Leave a comment