Jay Cohen, a Houston-based defense lawyer specializing in DUIs recently had a client with a curious case. When he got out to do the field sobriety test, the guy usually seemed fine. But then he blew into an alcohol tester and ended up with a test that was well above the limit.
What happened? "He was in great shape," says Cohen. One of those who do not miss a day in the gym. "So of course, he was on the keto diet." Being in ketosis could have caused the alcohol tester to turn out false positive. Armed with this information, Cohen dropped the DUI.
This can be done as follows: In ketosis, your liver builds up fat as fuel and produces acetone as a by-product. Part of this acetone is then released as isopropyl alcohol by your breath. The question is, can breathalyzers recognize the difference between ethanol and isopropyl alcohol? Depends on.
The cheap models people buy for self-examining their BAC are probably not accurate when they're on keto diet, says Alan Wayne Jones, professor of forensic technology at Linköping University in Sweden. These devices are based on semiconductor technology. Inside the device is a metal film that measures the resistance change based on the number of molecules that hit this film, explains Keith Nothacker, CEO of BACtrack a California-based breathalyzer manufacturer.
Basically, regular airflows from your lungs have a different amount of molecules than alcoholic air. From there, the device estimates your BAC, says Nothacker. Dr. However, Jones has never seen evidence that the devices can detect if these molecules are derived from ethanol or isopropyl.
Most police, however, carry alcohol-based fuel cell based breathalyzers ̵
One of the few papers available on this subject has been written by dr. Jones made. In 2006 he published a paper examining why a man on a low carb diet had a hard time launching a company car that was equipped with an alcoholic drinker. "In certain circumstances, acetone in the body can be converted to isopropanol, which like ethanol is oxidized by fuel cell respiratory analyzers," he says. "If a person drank isopropanol, they probably could not distinguish fuel cell instruments from ethanol, especially when combined with grain alcohol."
Nothacker does not believe, however. He says his company's fuel cell alcohol testers are ethanol specific and would not generate flow with isopropyl, which is a positive result. "In 17 years in the business," he says, "it has never been a problem."
And it does not matter: in many states, the preliminary breath test results can not be used in court. If you are arrested for a DUI, you are usually taken to the ward where you retest on a machine that uses infrared spectroscopy. These machines can tell the difference between isopropyl alcohol and ethanol, says Cohen. In some states, you can also request a blood test (usually at your expense), which in turn can tell the difference between the two alcohols.
Let's be clear: you say you are tripping on the keto diet During a field sobriety test, it will not be a free card coming out of jail. Officers rely on instincts to see if anyone is drunk or not, says Ranolph Rice, a DUI lawyer from Baltimore. "First, they start with the observation phase. Are there any signs that lead us to the next point? The smell is obviously the biggest sign, "he says. If you smell of alcohol, the officers have no sympathy for your diet.
In addition, it is probably rare for you to exceed the legal alcohol limit with a keto diet. If you drank one or two, maybe. But with acetone alone you probably can not blow .08, says Rice. He is more worried about customers who already had DUIs who now have breathalyzer ignition locks on their cars. In Maryland, these devices keep your car at a much lower level than the DUI limit. "If you blow a BAC of 0.02 or higher, you've broken your lock and they'll add another month to your program," says Rice. He assumes that theoretically a .02 could be achievable for a sober person with a keto diet.
Other illnesses can also cause alcohol testers to malfunction. Diabetes can lead to false positive results for the same reason as the keto diet. GERD or acid reflux can also be problematic. "If you have to bump or vomit, you have gastric alcohol. If it's in your mouth, it can read it, "says Cohen.
So what should you do if you get run over? Cohen and Rice both have the same very simple advice: never drink and drive. If you know that you are sober, ask to be returned to the station to use the infrared spectroscopy equipment. The blood test is more complicated, says Cohen. Although it is not a false positive result of a low-carbohydrate diet, it can catch something else – such as medications you take for ADHD or anxiety. "It will not look good with alcohol," he says, even if you are under the border. AC Shilton