Using evidence mapping to examine motivations for following plant-based diets

Authors: MIKI, AKARI - Tufts University; LIVINGSTON, KARA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; KARLSEN, MICAELA - University Of New England; FOLTA, SARA - Tufts University; MCKEOWN, NICOLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Current Developments in Nutrition
Publication Type: Review Article
Publication Acceptance Date: 1/20/2020
Publication Date: 3/3/2020
Citation: Miki, A.J., Livingston, K.A., Karlsen, M.C., Folta, S.C., Mckeown, N.M. 2020. Using evidence mapping to examine motivations for following plant-based diets. Current Developments in Nutrition. https://doi.org/10.1093/cdn/nzaa013.
DOI: https://doi.org/10.1093/cdn/nzaa013

Interpretive Summary:

Technical Abstract: BACKGROUND: Plant-based diets offer a healthier alternative to the typical Western diet. However, the methods for examining motivations to follow a plant-based diet are highly inconsistent. Better understanding of these motivations would improve characterization of current followers and could help with public health efforts to promote these diets. OBJECTIVE: Our objective was to use evidence mapping to identify variations in methods that capture motivations to follow plant-based diets, identify gaps in the literature on dietary motivations, and summarize demographic trends in dietary motivations with the available evidence. METHODS: We conducted searches in MEDLINE, CINAHL, and PsycINFO for studies on motivations to adopt plant-based diets (published 1946 to November 2018) and screened the publications with pre-defined criteria. We extracted and reported data on select variables using weighted scatter plots. RESULTS: We identified 56 publications that described 90 samples of plant-based diet followers. We categorized the samples by type of plant-based diet: vegan (19%), vegetarian (33%), semi vegetarian (24%), and general category of plant-based diet followers (23%). To capture dietary motivations, most studies administered multiple choice (31%), followed by rate items (23%), Food Choice Questionnaire (17%), free response (9%), and rank choices (10%). The most commonly measured motivations were health (100%), sensory/taste/disgust (69%), animal welfare (58%), environmental concern (59%), weight loss (53%), and unspecified ethics (41%). Evidence mapping indicates that the association between dietary motivations and type of plant-based diet appears strong, but evidence on the association between age and motivations remains inconclusive due to the few studies, small sample sizes, and underrepresentation of certain demographic groups. CONCLUSION: The observed methodological variation highlights the importance of using a validated questionnaire such as the Food Choice Questionnaire to investigate dietary motivations. Evidence maps can inform future studies examining the current appeal of plant-based diets as healthier and more sustainable alternatives to the typical Western diet.