Incorporating the dietary guidelines for Americans vegetable recommendations into the diet alters dietary intake patterns of other foods and improves diet quality in overweight adults and adults with overweight and obesity

Authors: Casperson, Shanon; JAHNS, LISA - National Institute Of Food And Agriculture (NIFA); Duke, Sara; Nelson, Alese; APPLETON, KATHERINE - Bournemouth University; Larson, Kate; Roemmich, James

Submitted to: Journal of the Academy of Nutrition and Dietetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2021
Publication Date: 4/4/2022
Citation: Casperson, S.L., Jahns, L., Duke, S.E., Nelson, A.M., Appleton, K.M., Larson, K.J., Roemmich, J.N. 2022. Incorporating the dietary guidelines for Americans vegetable recommendations into the diet alters dietary intake patterns of other foods and improves diet quality in overweight adults and adults with overweight and obesity. Journal of the Academy of Nutrition and Dietetics. https://doi.org/10.1016/j.jand.2022.03.008.
DOI: https://doi.org/10.1016/j.jand.2022.03.008

Interpretive Summary: It is well known that eating vegetables provide important health benefits. It is also known that US adults are currently not meeting the recommended vegetable intake levels set in the Dietary Guidelines for Americans (DGA). In addition, changes in daily intake levels of vegetables can lead to either increases or decreases in the amount of other foods consumed. As a result, this 8-week community-based study was conducted to determine the impact of increasing daily vegetable intake levels to that recommended by the DGA on dietary intake patterns. Overweight and obese adults who reported that they ate no more than one serving of vegetables each day were provided with the types and amounts of vegetables recommended by the DGA. Participants reported whether they substituted the provided vegetables for other foods. Dietary intake was also collected using the Automated Self-Administered 24-hour Dietary Assessment Tool. Some of the foods reported being displaced by the vegetables were snack foods, grains, and breads. In analyzing dietary recall records, we found that increasing vegetable consumption in accordance with DGA guidance resulted in decreases in the number of servings of grains, protein foods, saturated fats, and added sugars consumed. This paralleled an increase in total HEI scores and a decrease in the energy density of the diet. These results provide valuable insight into how habitual low-vegetable consumers incorporate vegetables into their diet and how this influenced other aspects of their diet. When providing vegetables in the amounts and types recommended by the DGA there appears to be a substitution effect that results in an improvement in overall diet quality, albeit modest. These findings highlight the importance of characterizing how individuals incorporate DGA recommendations into their diet, providing valuable information that can be used to develop targeted behavior change interventions.

Technical Abstract: Background: Understanding how vegetables are incorporated into the diet, especially in the types and amounts recommended by the Dietary Guidelines for Americans (DGA), and how this alters dietary intake patterns is vital for developing targeted behavior change interventions. Objective: To determine how adults with overweight and obesity incorporate DGA vegetable recommendations into their daily diet. We hypothesized that vegetables would be substituted into the diet, displacing energy-dense foods, resulting in lower energy intake and improved diet quality. Design: This study investigated secondary outcomes of an 8-week community-based randomized controlled trial. Participants/setting. Self-reported low vegetable consumers (n=55; attrition rate=8%) aged 18-65 years with a body mass index =25kg/m2 were recruited from the Grand Forks, ND, between October 2015 and January 2018. Intervention. DGA recommended types and amounts of vegetables were provided weekly for 8 weeks. Main outcome measures. Dietary intake was collected using the Automated Self-Administered 24-hour Dietary Assessment Tool. Substitution of the provided vegetables for other foods was reported daily. The Healthy Eating Index (HEI) 2015 and the Food, Attitudes and Behaviors Survey were also completed. Statistical analyses performed: Generalized linear mixed models where phase (pre, post) was the within-subject factor and subject was the random effect were used. Results: With the increase in vegetable consumption there were decreases in the number of servings of grains (p=0.0240), protein foods (p=0.0094), saturated fats (p=0.0125) and added sugars (p=0.0154) consumed. Total HEI-2015 scores increased (p=0.0013) and dietary energy density decreased (p<0.0001) in response to the intervention. Conclusions: When providing vegetables in the amounts and types recommended by the DGA there appears to be a substitution effect that results in an improvement in overall diet quality, albeit modest. These findings highlight the importance of characterizing how individuals incorporate DGA recommendations into their diet.