Incorporating the Dietary Guidelines for Americans Vegetable Recommendations into the Diet Alters Dietary Intake Patterns of Other Foods and Improves Diet Quality in Adults with Overweight and Obesity

Abstract

Background: Understanding how vegetables are incorporated into the diet, especially in the types and amounts recommended by the Dietary Guidelines for Americans, and how this alters dietary intake patterns is vital for developing targeted behavior change interventions.

Objective: To determine how a provision of vegetables was incorporated into the diet of adults with overweight and obesity; whether or not the provided vegetables displaced other foods; and what, if any, effect this had on diet quality and body weight and composition.

Design: This study investigated secondary outcomes from the Motivating Value of Vegetables Study, a community-based, randomized, parallel, nonblinded controlled trial. Participants were randomly assigned to a provided vegetable intervention or attention control group using a one to one allocation ratio.

Participants/setting: Men and women with self-reported low vegetable consumption, aged 18 to 65 years, with a body mass index ≥25 were recruited from Grand Forks, ND, between October 2015 and September 2017. Only participants randomized to the provided vegetable intervention group (n = 51; attrition = 8%) were included in this secondary analysis.

Intervention: Dietary Guidelines for Americans recommended types and amounts of vegetables were provided weekly for 8 weeks.

Main outcome measures: How the provided vegetables were incorporated into the diet was measured using daily self-report and 24-hour dietary recalls. Diet quality was assessed via the Healthy Eating Index 2015. Body weight and composition were measured before and after the intervention.

Statistical analyses performed: Data were assessed using generalized linear mixed models where phase (pre, post) was the within-subject factor and subject was the random effect.

Results: Participants self-reported using 29% of the provided vegetables as substitutes for other foods. With the increase in vegetable consumption, there were decreases in total grains (mean difference ± standard deviation; -0.97 ± 3.23 oz-equivalents; P = 0.02), protein foods (-1.24 ± 3.86 oz-equivalents; P = 0.01), saturated fats (-6.44 ± 19.63 g; P = 0.02), and added sugars (-2.44 ± 6.78 tsp-equivalents; P = 0.02) consumed. Total Healthy Eating Index 2015 scores increased (+4.48 ± 9.63; P = 0.001) and dietary energy density decreased (-0.44 ± 0.52 kcal/g; P < 0.0001). There was no change in total energy intake or body weight and composition.

Conclusions: Increasing vegetable consumption to meet Dietary Guidelines for Americans recommendations alters dietary intake patterns, improving diet quality and energy density. These findings highlight the importance of characterizing how individuals incorporate Dietary Guidelines for Americans recommendations into their diet.

Trial registration: ClinicalTrials.gov NCT02585102.

Keywords: Diet quality; Dietary Guidelines for Americans; Healthy Eating Index; Vegetables.