As the body goes into ketosis, it converts fats into ketone bodies, in particular beta-hydroxybutyrate, acetoacetate, and acetone, which cause bad breath. This is one of the common side effects of ketosis and also one of the most reliable indicators that you are in ketosis.
As far as the scientific explanation goes, it's all about the lungs and the blood vessels that supply them. As ketones circulate in the blood, they interact with small air sacs in the lungs. As ketones are exposed to the air in your body, they are expelled as a gas with the characteristic acetone odor.
How long will the acetone smell last?
Some people never experience this phenomenon, even if they are completely on the keto diet. Others experience it as a taste rather than a smell.
For most people who get that foul acetone odor, it lasts 2-5 weeks while your body readjusts itself to burn fat.
How to remove an unpleasant odor
There are some easy ways to eliminate this side effect, or at least reduce it enough so that it isn't a problem.
1. Drink plenty of water
Excess ketones are flushed out of the body through sweat and urine, so be sure to drink extra water during the ketogenic diet (with a pinch of salt to replenish electrolytes)
2. Take good care of your oral cavity
Extra brushing your teeth a day, as well as rinsing, can help alleviate this temporary problem.
3. Use mint and chlorophyll tablets
This breath freshening technique has a hidden impulse of deodorant ability, as chlorophyll helps neutralize odors through the body.
4. Wait
Bad breath may simply disappear after a few weeks. So be patient and wait.
5. Be less strict with yourself.
Try increasing your daily carbs by at least 5 grams and see if the acetone odor goes away. Keep in mind that everyone's body is different, so it's important to experiment with your carbohydrate dosage to keep your body in ketosis.
