To examine Australian adolescents’ knowledge and beliefs regarding potential health consequences of soda and diet soda consumption and nutritional aspects of soda and explore associations with consumption.

A survey utilising a nationally representative sample (stratified two-stage probability design) assessed knowledge of nutritional contents and health consequences of soda, and beliefs regarding health risks of diet soda, and soda and diet drink consumption.

Australia.

9102 Australian school students (12–17 years) surveyed in 2018.

Adolescents had lower nutritional knowledge (sugar content (22·2 %), exercise equivalent (33·9 %), calories/kJ (3·1 %)) than general knowledge of health risks (87·4 %) and some health effects (71·7–75·6 % for tooth decay, weight gain and diabetes), with lower knowledge of heart disease (56·0 %) and cancer (19·3 %). Beliefs regarding health effects of diet soda were similar, albeit not as high. In general, female sex, older age and less disadvantage were associated with reporting health effects of soda and diet soda, and nutritional knowledge of soda (P < 0·001). Those reporting tooth decay, weight gain, heart disease and diabetes as health effects of soda and diet soda were lower consumers of soda and diet drinks (P < 0·001), as were those with higher nutritional knowledge (sugar content and exercise equivalent; P < 0·001).

This study highlights possible knowledge gaps regarding the health effects of soda and nutritional knowledge for public health intervention. When implementing such interventions, it is important to monitor the extent to which adolescents may consider diet drinks as an alternative beverage given varied beliefs about health consequences and evolving evidence.