As a child, I was frequently told that crunchy foods were good for one’s teeth. Apples and carrots were usually the foods used as examples. I also remember thinking that, if crunchy foods were good for teeth, then surely jawbreakers, Jolly Ranchers, and Jordan almonds must be the best possible thing for my teeth, since there weren’t many foods crunchier than those.

While my logic may seem laughable, it raises the following question: When it comes to hard and crunchy foods, where is the line between beneficial and harmful? Not surprisingly, there are a number of conflicting answers, some even claiming that apples and carrots— supposed paradigms of tooth-friendly foods—could damage teeth. If it sounds confusing, let common sense and history be your guide.

Prevention magazine lists apples and carrots high on your teeth’s enemy list, but it’s because front teeth are fairly thin and often develop hairline fractures over time. Biting into hard foods, like apples and carrots, can stress and crack front teeth. Since apples and carrots have a real benefit by scrubbing teeth and gums while you chew, it’s best to cut hard, crunchy foods into bite-size pieces, which will eliminate any potential damage.

For other foods, it’s fairly easy to separate the good from the bad, because a pattern soon develops. Delta Dental created this basic list of the best crunchy foods:

  • Fiber-rich raw vegetable
  • Fiber-rich raw fruits
  • Nuts

What those three categories have in common is they were all part of our prehistoric past. It’s important to note that the foods Delta lists as the worst—popcorn, crackers, potato chips, pretzels, and peanut brittle—probably wouldn’t be found in our ancestor’s caves.

Britain’s Daily Mail makes a strong case that the evolution of food is the cause of everything from cavities to gum disease. For millions of years, humans ate a diet free of processed foods and sugars. Only in the last few hundred years have we been subjected to a soft, mushy diet. The food we eat has evolved faster than our bodies have. Eating more of the foods our cave-dwelling ancestors would have eaten, would benefit our oral health immensely.

The Smithsonian takes a slightly different view, claiming that our teeth, jaws, and gums began their demise when we switched from being hunter/gatherers to being farmers. There’s evidence that, after millions of years of eating meat and raw vegetables, the emergence of agriculture and softer, cooked foods created changes in our jaws and teeth from which we continue to suffer.

The answer to the original question of whether crunchy foods are good for teeth, is that crunchy fruits, vegetables, and nuts can clean teeth, stimulate saliva production, and hydrate the mouth, which all lessen the growth of bacteria. Crunchy processed foods contain sugar and starch which collect in the grooves of teeth and create a breeding ground for disease-causing bacteria.

When in doubt, eat like a caveperson. Just try to use better manners.