The South Beach Diet™ and Enter the Zone warn that "bad" carbs affect your waistline. That might be debatable, but one thing's for sure: "Bad" carbs are bad for your teeth. So bad, in fact, that they cause dental cavities.

Dental cavities, also known as tooth decay and dental caries, are a disease of the teeth that results in the destruction of tooth enamel. Dental cavities develop when foods containing "bad" carbohydrates -- such as soda, cake and candy -- are left on the teeth. Dental problems related to dental cavities result in more school absences than any other childhood disease.

Chances are, if you have dental cavities, you'll know soon enough. For example, years of gulping down an ice-cold soda every time you hear Def Leppard sing "Pour Some Sugar on Me" might eventually cause a toothache. That toothache is actually a common symptom of a dental cavity. Another telltale sign is bad breath. An easy way to spot a dental cavity is to simply look at your teeth -- if you see holes or pits, they are probably dental cavities. Some dental cavities, however, can only be detected by using dental X-rays or other sophisticated dental equipment.

Once you get a dental cavity, wishing it away won't do any good. Neither will chewing on the other side of your mouth. The only way to treat a dental cavity is to visit the dentist. Dentists usually treat dental cavities by removing the decayed part of the tooth and replacing it with a dental filling.

Dental fillings can be made of:

Amalgam -- Durable, easy to use, highly resistant to wear and economical. Amalgam is typically silver or black in color and contains mercury.

Composite -- A tooth-colored mixture of glass and quartz in a resin medium. Composite fillings are less noticeable than amalgam but not as durable.

Glass Ionomers -- A translucent, tooth-colored mixture of acrylic acids and fine glass powders.

Porcelain -- A ceramic material that mimics a tooth's natural color. Porcelain is very durable and virtually invisible to the naked eye.

It might be tempting to follow Ernestine Ulmer's advice, "Life is uncertain -- eat dessert first," but if you want to prevent dental cavities, skipping dessert is probably the better way to go. The fact is one of the simplest ways to preserve your teeth is to eat well-balanced, nutritious meals and to limit snacking.

Combining healthy eating habits with these steps can help reduce the risk even more:

• Brush twice a day with fluoride toothpaste.
• Floss daily.
• Use supplemental fluoride (if approved by your dentist).
• Ask your dentist about getting dental sealants.

Remember, dental cavities are an equal opportunity disease and anyone can suffer from them. Studies show that cavities are particularly common in children and young adults, and that rates have been fuelled by an increase in sugars in the diet and bad oral habits. But your teeth have a good chance at remaining healthy and decay-free if you practice good oral hygiene and schedule regular dental visits every six months.