The rotten-trash-heap breath you get with a low-carb diet, on the other hand, is a whole other beast that occurs when ketones are released, not because there's more bacteria than usual. In fact, forgoing sugar and starchy foods may actually be good for your oral health.
“Foods high in sugar and carbohydrates can create acidic environments in the mouth,” Dr. Aldredge says. “The bacteria that can lead to periodontal disease thrive in these kinds of environments, feeding off of the sugar that lingers from the food we eat.”
Unfortunately, that also means ketosis breath can’t be extinguished with the typical handful of mints and swig of mouthwash. Some natural remedies may help, such as drinking extra water, or chewing on fresh mint leaves, cloves, or fennel seeds, Dr. Aldredge says. For a temporary fix, he also suggests reaching for sugar-free gum made with xylitol.