Often the goal of low carb diets is to move the body into ketosis, which helps it burn fat. During ketosis, the body produces ketones, which have a notable odor. One way to minimize the smell of ketones is to drink more water. If the smell is bad enough, you might consider giving up the diet. It’s up to you and your doctor to weigh the pros and cons of losing weight versus having bad breath.
Tonsil stones are small formations that develop in pockets within the tonsils. When you look in your mouth, you may see the white or yellow formations that are causing your breath to change for the worse. Tonsil stones are not growths. They typically don’t pose a health concern. They are more of a nuisance that can create mild discomfort depending on size (stones can range from the size of a grain of rice to a grape).

For decades after Listerine first hit the market in the 1880s, it was kind of a jack-of-all trades product. Originally invented as a surgical antiseptic (and named after the founding father of antiseptics, Dr. Joseph Lister), its uses were varied—they including foot cleaning, floor scrubbing and gonorrhea treating.
Smell and taste belong to our chemical sensing system (chemosensation). The complicated process of smelling and tasting begins when molecules released by the substances around us stimulate special nerve cells in the nose, mouth, or throat. These cells transmit messages to the brain, where specific smells or tastes are identified. Olfactory (smell nerve) cells are stimulated by the odors around us, the fragrance from a rose, the smell of bread baking. These nerve cells are found in a tiny patch of tissue high up in the nose, and they connect directly to the brain. Gustatory (taste nerve) cells are clustered in the taste buds of the mouth and throat. They react to food or drink mixed with saliva. Many of the small bumps that can be seen on the tongue contain taste buds. These surface cells send taste information to nearby nerve fibers, which send messages to the brain.