Objectives: To determine the association of overweight/obesity, dental caries and dietary sugars in Australian adults.

Materials and methods: The National Survey of Adult Oral Health (NSAOH) 2004–2006 provided data for analysis of dental caries experience. Self‐reported body weight and height were used to calculate body mass index (BMI) for a subsample (n = 3,745, 89.8%) of the NSAOH data. A self‐report questionnaire of 13 food items estimated the daily intake of added sugar, total sugars and total carbohydrate, using food composition estimates from the AUSNUT2011-2013. Bivariate analyses (Pearson's Chi‐square with Rao–Scott adjustment and Student's t‐tests) were used to determine the association of overweight/obesity, dental caries, sugar variables and putative confounders. Poisson regression models for the Decayed, Missing and Filled Teeth Index and individual measures of decayed, missing and filled teeth were constructed, with models containing BMI, dietary added sugar, total sugar and total carbohydrate, controlling for putative confounders.

Results: There was a positive association between dental caries experience and being overweight or obese compared with having normal weight or being underweight as well as between sugar consumption with all four dental caries outcome measures. When controlled for putative confounders where sugar consumption was identified as a key determinant, the statistical significance between dental caries experience and being overweight or obese disappeared. The demographic and socioeconomic factors associated with dental caries experience were age, sex, education, smoking status and usual reason for dental visit.

Conclusion: Analysis of the relationship between dental caries and obesity must include data about sugar and carbohydrate consumption.