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If you want to prevent cavities, how often you eat can be just as important as what you eat. That's because food affects your teeth and mouth long after you swallow.

Dental Plaque​

Dental plaque is a biofilm that develops naturally on teeth. This plaque contains bacteria, which create acid when they metabolize food (carbohydrates). When you eat, the bacteria eat. As this acid accumulates, it begins to break down the enamel on your teeth. This starts the process of cavity formation.

Fermentable Carbohydrates

All carbohydrate foods eventually break down into simple sugars: glucose, fructose, maltose and lactose. Some foods, called fermentable carbohydrates, break down in the mouth, whereas others don't break down until they move further down the digestive tract.

​Fermentable carbohydrates include sugary foods, such as cookies, cakes, soft drinks and candy, but also include less obvious food, such
as bread, crackers, bananas and breakfast cereals.

Bacteria within the plaque on your teeth use the sugars from these foods and produce acids. These acids dissolve minerals inside the tooth
enamel in a process called demineralization. Saliva helps this process, as does fluoride and some foods.

​The longer food stays near the bacteria on the tooth, the more acids will be produced.

​Sticky carbohydrates, such as raisins, can have prolonged effects. Snacks like this don’t create acids on your teeth only while they are being eaten. The acids stick around for the next half-hour.

​By sipping sweetened drinks throughout the day or eating many carbohydrate snacks, dental bacteria can produce acid almost constantly. Studies have shown that those who eat sweets as snacks between meals have higher incidences of decay than those who eat the same amount of sweets with their meals.

Chewing sugarless gums also can help protect your teeth against cavities. Xylitol, an ingredient in some sugarless gums, has been shown to reduce the amount of bacteria in the mouth and help buffer the teeth against the effect of acid. Most sugarless gums and sugarless candies increase the flow of saliva, which has natural antibacterial properties.

What To Eat

​Below is a list of Dietary Guidelines developed by the U.S. Department of Agriculture and the Department of Health and Human Services.

  • Eat whole grains daily, such as brown rice, oatmeal and whole wheat bread
  • Limit refined grains, such as white bread and white rice.
  • Eat healthier vegetables, including dark green and orange vegetables.
  • Eat a variety of fruits.
  • Choose a diet with plenty of grain products, fruits and vegetables.
  • Choose fish, beans, nuts and seeds for some of your protein needs.
  • Choose beverages and foods to moderate your intake of sugars.
  • Choose and prepare foods with less salt.
  • If you drink alcoholic beverages, do so in moderation.
  • Aim for a healthy weight and be physically active each day.


To prevent tooth decay, you should follow a few additional guidelines to keep the amount of acid created by the bacteria on your teeth to a minimum. Here are some tips.


Limit snacking to reduce the amount of time your teeth are exposed to acid. If you snack, choose foods that are not fermentable carbohydrates.


  • Best choices — Cheese, chicken or other meats, nuts or milk. These foods may actually help protect tooth enamel by counteracting acidity or by providing the calcium and phosphorus needed to remineralize teeth.

  • Moderate choices — Firm fruits like apples and pears and vegetables. Although firm fruits contain natural sugars, they have a high water content that dilutes the effects of the sugars and they stimulate the flow of saliva, which has antibacterial factors and helps protect against decay. Vegetables do not contain enough carbohydrates to be dangerous.

  • Worst choices — Candy, cookies, cakes, crackers, breads, muffins, potato chips, french fries, pretzels, bananas, raisins and other dried fruits. These foods provide a source of sugar for certain bacteria on the teeth to produce acid. The problem can be worse if the foods stick to or get caught between teeth.

Limit the amount of soft drinks or any other sugar-containing drinks, including coffee or tea with added sugar, cocoa and lemonade. Fruit juices contain natural sugars that can also cause decay. Limit the amount of time you take to drink any of these drinks and avoid sipping them throughout the day. A can of soda finished with a meal is better than a can of soda finished over two hours because your teeth are exposed to high acid levels for a shorter amount of time.


  • Better choices — Unsweetened tea, milk and water, especially fluoridated water. Tea also has fluoride, which can strengthen tooth enamel and milk can also help deter decay. Water helps flush away food debris and can dilute the sugar acids.

Avoid sucking on hard candies or mints, even the tiny ones. They have enough sugar to increase the acid produced by bacteria to decay levels. If you need a mint, use the sugarless varieties.


Very acidic foods (such as citrus fruits) can make the mouth more acidic and may contribute to tooth demineralization and erosion. The effects of acid exposure are cumulative, so every little bit counts.


Brush your teeth after eating to remove the plaque bacteria that create the destructive acids. If you cannot brush after every meal, brush at least twice a day to thoroughly remove all plaque bacteria.


Chewing sugarless gum that contains xylitol can help reduce the risk of cavities. It not only helps dislodge some of the food stuck to your teeth, it also increases saliva flow to help buffer the acids.