Purpose: Rebalancing the contribution of animal- and plant-based foods is needed to achieve sustainable diet. However, little is known concerning individual characteristics that may influence intake of plant-based foods and their changes over time. We aimed to assess changes in the contribution of plant-based foods to dietary intake over time and their association with individual characteristics.
Methods: The contribution of plant-based foods was assessed by percent energy intake provided by plant proteins in diet (PEIPP) and a score of adherence to a pro-vegetarian diet, using repeated 24-h records in 15,615 French adults participating in the NutriNet-Santé cohort study. Associations between baseline individual characteristics and changes in the two indicators over a 4-6-year follow-up were assessed using a linear mixed model.
Results: At baseline, PEIPP and pro-vegetarian score were positively associated with age [β65+ = 0.80, 95% CI = (0.71, 0.88), β65+ = 3.30, 95% CI = (2.97, 3.64), respectively] and education [βpostgraduate = 0.23, 95% CI = (0.12, 0.34), βpostgraduate = 1.19, 95% CI = (0.75, 1.62)], while they were inversely associated with BMI class [βobesity = - 0.48, 95% CI = (0.56, 0.41), βobesity = - 2.31, 95% CI = (- 2.63, - 1.98)]. Men had higher PEIPP than women [β = 0.06, 95% CI = (0.01, 0.11)]. Pro-vegetarian score significantly increased over time [β = 0.23, 95% CI = (0.08, 0.37)]. The older the individual at baseline, the greater the decrease in the two indicators during follow-up. Pro-vegetarian score increased during follow-up for obese participants at baseline.
Conclusions: The contribution of plant-based foods was associated with several socio-demographic and economic characteristics at baseline, whereas change over time was related to age and weight status. Further analysis of individual obstacles and lever to consume plant-based foods is needed.
Keywords: Dietary change; Individual characteristics; Longitudinal analysis; Plant proteins; Plant-based foods; Sustainable diet.