Diet and nutrition impact on many oral diseases, in particular dental caries. Consumption of fluoridated water coupled with a reduction in non-milk extrinsic sugar intake is an effective means of caries prevention. However, studies on the fluoride concentration of bottled waters suggest increased consumption of these waters, in preference to fluoridated tap water, would lead to a marked decrease in caries protection. Concerns have been raised about the bioavailability of fluoride from artificially-fluoridated water compared with naturally-fluoridated water. This issue has been addressed in a human experimental study that has indicated that any differences in fluoride bioavailability are small compared with the naturally-occurring variability in fluoride absorption. Research has unequivocally shown sugars to be the main aetiological factor for dental caries, and information on intakes guides health promotion. Repeat dietary surveys of English children over three decades indicate that levels of sugars intake have remained stable, while sources of sugars have changed considerably, with the contribution from soft drinks more than doubling since 1980. Dental caries eventually leads to tooth loss, which in turn impairs chewing ability causing avoidance of hard and fibrous foods including fruits, vegetables and whole grains. A very low intake (<12 g/d) of NSP and fruit and vegetables has been found in edentulous subjects. Provision of prostheses alone fails to improve diet. However, initial studies indicate that customised dietary advice at the time of denture provision results in increased consumption of fruits and vegetables, and positive movement through the stages of change. Feasible means of integrating dietary counselling into the dental setting warrants further investigation.