The Keto Diet - a low-carb, high-fat diet - is designed for weight loss but it does have an unpleasant side effect -- bad breath.
Main points:
- When on the diet, ketones produced in the liver cause a rotting fruit/metallic smell.
- Keep hydrated with water, chewing mints or gum containing xylitol helps.
- Brush teeth twice a day and floss.
There are other reasons for bad breath. Make sure you see a dentist for regular check-ups.
"If you're doing well on the keto diet...you can still stay in ketosis and treat your bad-breath situation."
More:
https://www.popsugar.com/fitness/Why-Does-Keto-Diet-Give-You-Bad-Breath-45048410