Trends in the Number of Behavioural Theory-Based Healthy Eating Interventions Inclusive of Dietitians/Nutritionists in 2000–2020

Nutrition interventions developed using behaviour theory may be more effective than those without theoretical underpinnings. This study aimed to document the number of theory-based healthy eating interventions, the involvement of dietitians/nutritionists and the behaviour theories employed from 2000 to 2020. We conducted a review of publications related to healthy eating interventions that used behaviour change theories. Interventional studies published in English between 2000 and 2020 were retrieved from searching Medline, Cinahl, Embase, Psycinfo and Cochrane Central. Citation, country of origin, presence or absence of dietitian/nutritionist authors, participants, dietary behaviours, outcomes, theories and any behaviour change techniques (BCTs) stated were extracted. The publication trends on a yearly basis were recorded. A total of 266 articles were included. The number of theory-based interventions increased over the two decades. The number of studies conducted by dietitians/nutritionists increased, but since 2012, increases have been driven by other researchers. Social cognitive theory was the most used behaviour theory. Dietitians/nutritionists contributed to growth in publication of theory-based healthy eating interventions, but the proportion of researchers from other professions engaged in this field increased markedly. The reasons for this growth in publications from other professions is unknown but conjectured to result from greater prominence of dietary behaviours within the context of an obesity epidemic.