Confusion and nutritional backlash from news media exposure to contradictory information about carbohydrates and dietary fats.

Objective: To test the effect of news media exposure to contradictory information about carbohydrates and dietary fats on levels of confusion, nutritional backlash and dietary intentions. Design: We conducted an online survey experiment between 11 and 28 February 2018, randomizing participants to one of six experimental conditions. Two 'contradictory information' conditions asked participants to read one news article on the risks of a low-carbohydrate diet and one article on the risks of a low-fat diet. Two 'convergent information' conditions asked participants to read two articles with similar information on the risks of one of these two diets. A fifth 'established health recommendations' control condition asked participants to read two articles on the harms of smoking and sun exposure. A sixth 'no information' condition served as a second control group. We used general linear models to test hypotheses on the effects of exposure on confusion, nutritional backlash and dietary intentions. Setting: USA. Participants: Adults (n 901) registered with Amazon's Mechanical Turk (M-Turk). Results: Exposure to contradictory information about carbohydrates and dietary fats increased confusion and nutritional backlash compared with exposure to established health recommendations for non-dietary behaviours and a no-exposure control. Exposure to contradictory information also increased confusion compared with exposure to consistent nutrition information regarding carbohydrates and dietary fats. Conclusions: Contradictory nutrition information in the news media can negatively affect consumers' attitudes, beliefs and behavioural intentions. Dietary debates that play out in the media may adversely influence both short-term dietary decisions and future efforts to communicate about unrelated nutrition issues.