The document discusses the role of carbohydrates in dental caries (tooth decay). It states that fermentable carbohydrates like glucose, fructose, and sucrose are easily fermented by bacteria like Streptococcus mutans in dental plaque, producing acids that demineralize tooth enamel and lead to cavities. Frequent sugar intake and sticky carbohydrates that remain on teeth increase caries risk. Starches carry less risk as they are slowly broken down. Replacing sucrose with non-fermentable sugars can reduce caries. Local acid production below pH 5.5 causes subsurface enamel demineralization and below pH 4-5 leads to surface enamel loss.