If you’re attempting a very-low-carb diet, you may get something else besides weight loss. Very-low-carb diets are ways to achieve ketosis, a natural process that forces your body to fuel the brain and other organs with stored fat rather than the usual carbs.
One of the more unsavory side-effects of ketosis is known as “keto-breath.” This process causes the body to emit certain chemicals called ketones, and when you exhale, these smell similar to acetone, the principle ingredient in nail polish remover.
If you’ve been low-carb dieting and notice a slightly sweet chemical smell coming from your mouth, forget asking your dentist for help, because this is one bad breath cause that can’t be overcome with better oral hygiene. Instead, you’ll need to either change your diet or mask the smell somehow. Mouthwash may be your best bet. You could try sugar-free gums or lozenges too, but be careful—even the sugar-free varieties often come loaded with carbs, which will throw off your weight-loss plan.