Adherence to a culturally adapted soul food vegan diet among African American adults increases diet quality compared to an omnivorous diet in the NEW Soul Study

Abstract

Adherence to a vegan diet may lower risk of cardiovascular disease among African Americans (AAs). Feasibility and sustainability of adopting a vegan diet may be challenging among AAs who live in regions where soul food is a predominant cuisine. Our hypothesis was that AAs randomized to a culturally adapted vegan diet will have greater adherence to their assigned diet compared to those randomized to a culturally adapted omnivorous diet. AAs (N=113) with overweight/obesity from South Carolina were included. Dietary intake was measured at months 0, 3, 6, and 12 using 24-hr recalls. Adherence was defined based on recommended animal product intake for each group. Differences in nutrient intakes and dietary indices [Alternative Healthy Eating Index 2010 (AHEI-2010) and healthy plant-based diet index (hPDI)] between groups were evaluated using t-tests. At 12 months, adherence was higher to the vegan (51%) versus omnivorous (35%) diet. Participants assigned to the vegan diet had higher intake of carbohydrates (P=0.01) and fiber (P<0.001), and lower intake of cholesterol P<0.001) and protein (P=0.001) compared to participants assigned to the omnivorous diet. Participants adherent to the vegan diet had lower cholesterol intake P<0.001) and higher fiber intake (P=0.02) compared with those adherent to the omnivorous diet. Compared to those assigned to the omnivorous diet, participants assigned to the vegan diet had higher AHEI-2010 (P=0.01) and hPDI (P<0.001) scores. AAs with overweight/obesity were more adherent to a culturally adapted vegan diet versus an omnivorous diet after 1 year, and nutrient and food group intake changes were sustained.

Graphical Abstract

We analyzed data from 113 African Americans with overweight/obesity from the Nutritious Eating with Soul Study. Compared to participants assigned to a culturally adapted omnivorous diet, participants assigned to a culturally adapted vegan diet had greater adherence, higher consumption of carbohydrates and fiber, lower consumption of cholesterol and protein, and higher diet quality after 1 year. AHEI-2010, Alternative Healthy Eating Index 2010; hPDI, healthy plant-based diet index

INTRODUCTION

Healthful, plant-based dietary patterns are associated with improved health outcomes, lower risk of chronic conditions, and lower risk of mortality (1-4). Specifically, consumption of a vegan dietary pattern is associated with positive changes in biomarkers and lower risk of hypertension, diabetes, and high cholesterol compared with an omnivorous diet (5-9). While many studies have reported positive outcomes, it can be challenging to implement these behavior changes in practice. It is especially challenging when considering African American (AA) foodways that have more variation in preferences for food choices and flavor (10-13). Making healthful dietary patterns accessible and adaptable to a population’s regional and cultural background is crucial for adherence and adaptability.

A low-fat omnivorous diet, characterized by limited animal products, low-fat dairy, fruits, vegetables, and legumes, is similar to a Healthy US-Style Eating pattern, which has been found to reduce weight and systolic and diastolic blood pressures among AAs (14). Previous studies have shown that AA adults have lower adherence to this diet compared to white adults, and therefore alternative dietary patterns such as a culturally tailored vegan diet may be promising (14, 15).

AAs have a disproportionately higher prevalence of obesity and cardiovascular disease (CVD) risk factors compared with white individuals (16). While there is promising evidence that adherence to a vegan dietary pattern may reduce risk of CVD risk factors among AA adults (17), previous studies have identified that a major barrier to consuming plant-based diets among AA adults include the perception that vegan diets are not aligned with cultural identity and acceptability (11-13). Soul food is an ethnic cuisine that originated in Southern United States that is traditionally prepared and eaten by AAs and is closely tied to AA’s cultural identity. Its early roots in the 1400s suggests that most West African tribes ate a plant-based diet, which has led to a recent movement prompting the opening of vegan soul food restaurants in the South (18). Soul food often contains fried chicken, chitlins, or pork, as well as green vegetables, okra, and black-eyed peas. Plant-based soul food includes using plant-based proteins for “mock meat” and sides such as collard greens, sweet potatoes, or other vegetables (18).

Few studies have investigated the impact of a behavioral intervention that focuses on a culturally adapted vegan diet on dietary outcomes. The Nutritious Eating with Soul (NEW Soul) study sought to improve acceptability of a vegan diet among AAs through group-based nutrition counseling and cooking demonstrations from local AA soul food restaurant owners, as well as digital support and content.

We hypothesized that AAs randomized to a culturally adapted vegan diet will have greater adherence to their assigned diet compared to those randomized to a culturally adapted omnivorous diet. We tested this by characterizing adherence to the vegan and omnivorous diets and assessing differences in dietary and nutritional quality among AAs living in the Midlands region of South Carolina.

METHODS AND MATERIALS

The methods for the NEW Soul study are described in detail elsewhere (19, 20, 21). Briefly, the NEW Soul study was a two-year randomized trial beginning in 2018 that compares a plant-based, vegan diet and low-fat, reduced animal product, omnivorous diet, among AA adults aged 18 to 65 years with overweight or obesity. It aimed to use an innovative intervention to improve dietary intake while maintaining traditional cultural food choices among AA adults living in the Midlands of South Carolina by incorporating education on plant-based diets and meal preparation. The study was designed to examine the primary outcomes of differences in CVD risk factors and body weight at 12 months between participants randomized to the vegan or omnivorous diets.

Adults with overweight or obesity (BMI 25-49.9 kg/m²) who self-identified as AA were recruited from a southeastern city through community events, news stories, and radio ads. After completing a screening questionnaire, attending an orientation session, and completing all baseline assessments, participants were randomized to follow either a 1) whole foods, plant-based vegan diet or a 2) low-fat omnivorous diet. Both diets centered around soul food cuisine and neither group was provided with energy restrictions. Both groups were provided with the same physical activity recommendations (gradual increase to 75 minutes of vigorous activity or 150 minutes of moderate, or combination, each day) and a daily B12 supplement to take. The intervention was conducted in two cohorts separated by one year beginning in 2018. The study consisted of weekly in-person meetings for 6 months (26 meetings lasting 75 minutes each), followed by bi-weekly meetings for 6 months (13 meetings), and then monthly meetings for the last 12 months (12 meetings). Due to the COVID 19 pandemic, bi-weekly classes for cohort 2 were delivered via Zoom. All changes that resulted from the COVID pandemic are detailed elsewhere (21). Classes were led by an RDN-trained nutrition interventionist, MPH-trained project manager, and discussion facilitators from the community. AA soul food restaurant owners and chefs provided cooking demonstrations and sample foods. The nutrition interventionist worked with chefs to ensure recipes met the study’s nutrition recommendations. All classes followed a similar format including reviewing the previous week’s goal, a group discussion of any successes or challenges with the diet, an overview of a nutrition topic, a coking demo or hands-on cooking activity, an in class exercise or stress management activity, and a goal setting activity for the next week, In addition to in-person group classes, participants received weekly emails with class handouts and recipes. At 6 months, participants were able to join a private Facebook group for their diet group. At 12 months, participants received content through podcasts, online newsletters, and face-to-face meetings.

Ethics

The University of South Carolina’s institutional review board approved this study (approval number Pro00064855). In addition, the study was overseen by a three-member Data Safety and Monitoring Board. Informed consent was obtained from all participants. Participants were provided with financial incentives at each assessment timepoint ($10 at 3 months, $50 at 6 months, $50 at 12 months, and $100 at 24 months). This trial was registered at clinicaltrials.gov as NCT03354377.

Dietary Interventions

Participants in the vegan group were instructed to abstain from all animal products (meat, poultry, fish, eggs, and dairy). Participants in the omnivorous group were instructed to consume limited amounts of animal products (no more than 5 ounces of lean meat per day; no more than 2 egg yolks per week; two servings of fish per week) based on the recommendations of the Therapeutic Lifestyle Changes (TLC) diet (22). Both diets drew intervention content from the Oldways African Heritage Diet (23). Both dietary intervention groups received a handout that detailed portion sizes for each food group (grains, vegetables, legumes, fruit, vegetable oils/essential fatty acids, nuts/seeds, treats, beverages, meat, fish, poultry, and eggs, dairy, sodium and seasonings, Vitamin B12, and alcohol) (19).

Assessment of Diet

Diet was assessed at months 0, 3, 6, and 12. Diet was assessed using the National Cancer Institute’s Automated Self-administered 24-hour recall (ASA24) (24). At each time point, intake was assessed on three unannounced days (2 weekdays and 1 weekend day) and collected within a three-week window. The average of nutrients and food group intake from the three recalls were calculated for each time point. All participants received an in-person training on the ASA24 at baseline and completed their first recall in-person. All subsequent recalls were completed remotely as the ASA24 can be accessed online or via smartphone. Intake from supplements was not included in the analyses so only foods (both fortified/enriched and not) were included in the ASA24 analyses.

Dietary adherence was scored based on the recommended amounts of animal product servings/d of 5 groups of foods on the averaged dietary recalls: eggs, seafood, poultry, red meat, and dairy (Supplemental Table 1). For the vegan diet, a point was awarded for the absence of each of the food groups, whereas 0 points were awarded for >0 servings/d. For the omnivorous diet, a point was awarded for the following: eggs ≤0.3 servings/d, seafood ≥0.3 servings/d, poultry ≤1 serving/d (3 oz/d), red meat ≤0.67 servings/d (2 oz/d), and dairy ≥2 servings/d. If the threshold was not met, 0 points were awarded for that component. For each diet, total scores could range from 0 to 5, with 5 being most adherent. The continuous score was dichotomized into adherent (score ≥2.5) or non-adherent (score <2.5).

Scoring of dietary patterns

Alternative Healthy Eating Index 2010 (AHEI-2010) and healthy plant-based diet index (hPDI) scores were calculated. The AHEI-2010 score was developed based on foods and nutrients identified to be associated with the risk of chronic disease in previous literature (25). Though the original AHEI-2010 includes 11 components and ranges from 0 to 110, we only included 9 components due to lack of output on some foods and nutrients from ASA24, with a total score range from 0 to 90 (Supplemental Table 2). We included total vegetables, total fruit, whole grains, nuts and legumes, long-chain fats, polyunsaturated fats, red/processed meat, sodium, and alcohol. Because ASA24 output does not report both trans-fat and sugar-sweetened beverages and fruit juice, those score categories could not be included. Each of the nine components were scored based on serving cut-offs from 0 to 10, with 10 being optimal.

The hPDI is made up of plant food groups (broken up into healthy and less healthy) and animal food groups (3). Healthy plant-based food groups included vegetables, fruits, whole grains, nuts, legumes, and vegetable oils; less healthy plant-based food groups included fruit juices, refined grains, potatoes; and animal food groups included animal fat, dairy, egg, fish or seafood, and meat (Supplemental Table 3). Each of the 14 components has a possible score of 1-5, based on ranked quintile of consumption, with 5 being optimal. We omitted tea and coffee, sugar sweetened beverages, sweets and desserts, and miscellaneous animal-based foods components (which are in the original score) from our score due to not having this output from ASA24. The total possible score ranged from 14 to 70, with 70 being an optimal diet score.

Statistical Analyses

Only participants who had data at each time point were included in the analyses. Using the dichotomized adherence score, we calculated the percentage of participants who were adherent at each time point by assigned intervention group.

We calculated mean ± standard error (SE) nutritional intake by assigned intervention group and differences in nutritional intake between groups at month 0 and at months 3, 6, and 12, adjusted for consumption at month 0 using linear regression models. In a sensitivity analysis, we used a mixed linear model with random intercept for individuals to account for attrition. We also calculated mean nutritional intake by adherence status for the vegan and omnivorous diet at months 3, 6, and 12, adjusted for consumption at month 0. We calculated total and components scores for AHEI-2010 and hPDI at months 0, 3, 6 and 12 by assigned intervention group. Additionally, t-tests were used to examine differences in nutritional intake between groups. All analyses were conducted using Stata (version 17.0; StataCorp).

RESULTS

Baseline demographics and study completion rates for the NEW Soul study have been published previously (21). Of the 159 participants in the NEW Soul study, 113 participants (53 assigned to vegan diet; 60 assigned to omnivorous diet) had complete dietary recalls at months 0, 3, 6, and 12 and were therefore included in the present analysis (Supplemental Figure 1). Demographics for the total study sample and by adherence at 12 months are displayed in Table 1. Participants had a mean age of 50.6 years and 81% were female. Main outcomes of the study have also been previously published examining all participants, regardless of adherence status, and there were no significant differences in any of the outcomes, such as weight or lipids, between the groups (21).

Table 1.

Baseline characteristics of 113 African Americans with overweight/obesity of the NEW Soul study, overall and by adherence status at 12 months¹.

Adherence Group
Characteristics	Total (N=113)	Vegan adherent (n=27)	Vegan non- adherent (n=26)	Omni adherent (n=21)	Omni non- adherent (n=39)
Female, n (%)	92 (81%)	19 (70%)	22 (85%)	18 (86%)	33 (85%)
Age, years	50.6 ± 10.0	53.0 ± 7.5	50.9 ± 10.3	48.9 ± 11.7	49.7 ± 10.4
Education, n (%)
Some college or less	26 (23%)	10 (37%)	3 (12%)	2 (10%)	11 (28%)
College	41 (36%)	10 (37%)	12 (46%)	6 (29%)	13 (33%)
Advanced degree	46 (41%)	7 (25%)	11 (42%)	13 (62%)	15 (38%)
Employment, n (%)
Employed	97 (86%)	21 (78%)	22 (85%)	21 (100%)	33 (85%)
Not employed	16 (14%)	6 (22%)	4 (15%)	0 (0%)	6 (15%)
Marital Status, n (%)
Single	29 (26%)	5 (19%)	6 (23%)	10 (48%)	8 (21%)
Married	58 (51%)	16 (59%)	13 (50%)	8 (38%)	21 (54%)
Divorced/separated	23 (20%)	5 (19%)	6 (23%)	2 (10%)	10 (26%)
Widowed	3 (3%)	1 (4%)	1 (4%)	1 (5%)	0 (0%)

¹Values are means ± SDs for continuous variables or n (%) for categorical variables.

Abbreviations: omni, omnivorous

Adherence to Vegan and Omnivorous Diet Interventions

Supplemental Table 1 presents the adherence rates for the two diets at 3, 6, and 12 months by assigned intervention group. We found that 60% (n=32), 43% (n=23), and 51% (n=27) of participants assigned to the vegan diet intervention were adherent at 3, 6, and 12 months, respectively. Additionally, 33% (n=20), 30% (n=18), and 35% (n=21) of participants assigned to the omnivorous diet intervention were adherent at 3, 6, and 12 months, respectively.

Nutrient intake

Compared to the group assigned to the omnivorous diet (n=60), the group assigned to the vegan diet (n=53) had, on average, a higher intake of carbohydrates (mean difference ± SE: 33.9 ± 13.1 g; P=0.01) and fiber (mean difference ± SE: 7.8 ± 2.0 g; P<0.001), and lower intake of cholesterol (mean difference ± SE: −140.6 ± 25.5 mg; P<0.001), protein (−16.0 ± 4.8 g; P=0.001) compared to the group assigned to the omnivorous diet at 12 months (Table 2). Total energy intake was comparable between the two groups, but carbohydrates (% energy) was higher for the vegan group (P<0.001) and protein (% energy) (P<0.001) and sodium (% energy) (P=0.04) was higher for the omnivorous group. Trends were similar at months 3 and 6. In our sensitivity analysis, using mixed linear model with random intercept, we found similar patterns (Supplemental Table 2).

Table 2.

Nutritional intake¹ by randomized group at months 0, 3, 6, and 12 among African Americans with overweight/obesity.

Macro- and Micronutrients	Month 0				Month 3				Month 6				Month 12
	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P
Absolute Intake
Total energy, kcal/d	1953 (80)	1972 (75)	−19 (110)	0.9	1335 (78)	1403 (73)	−67 (107)	0.5	1484 (65)	1487 (61)	−3 (89)	0.9	1518 (72)	1443 (67)	75 (99)	0.5
Total fat, g	82.2 (4.0)	83.8 (4.3)	−1.6 (5.9)	0.8	44.8 (3.3)	53.7 (3.1)	−8.9 (4.5)	0.05	52.2 (3.1)	58.8 (2.9)	−6.7 (4.3)	0.1	57.0 (4.0)	55.8 (3.8)	1.2 (5.5)	0.8
Saturated fat, g	24.1 (1.4)	25.0 (1.4)	−0.9 (2.0)	0.6	9.7 (1.0)	14.0 (0.9)	−4.3 (1.3)	0.002	12.3 (0.9)	15.4 (0.8)	−3.1 (1.2)	0.01	12.9 (1.1)	15.5 (1.0)	−2.6 (1.4)	0.1
Monounsaturated fat, g	29.7 (1.4)	29.8 (1.6)	−0.1 (2.2)	0.9	16.0 (1.3)	19.6 (1.2)	−3.6 (1.8)	0.05	19.2 (1.3)	21.2 (1.2)	−2.0 (1.7)	0.2	21.0 (1.7)	19.8 (1.6)	1.1 (2.4)	0.6
Polyunsaturated fat, g	21.7 (1.3)	22.5 (1.4)	−0.9 (1.9)	0.7	15.4 (1.0)	15.6 (1.0)	−0.2 (1.4)	0.9	16.3 (1.1)	17.4 (1.1)	−1.0 (1.5)	0.5	18.5 (1.4)	15.7 (1.3)	2.8 (1.9)	0.1
Cholesterol, mg	338.9 (18.5)	321.8 (24.5)	17.1 (31.3)	0.6	51.8 (16.0)	202.4 (15.1)	−150.6 (22.0)	<.001	67.7 (17.0)	216.3 (16.0)	−148.6 (23.3)	<.001	74.1 (18.6)	214.7 (17.5)	−140.6 (25.5)	<.001
Carbohydrates, g	214.8 (10.2)	218.4 (8.2)	−3.6 (12.9)	0.8	195.4 (11.9)	168.1 (11.2)	27.3 (16.3)	0.1	208.8 (8.7)	173.5 (8.1)	35.3 (11.9)	0.004	204.7 (9.6)	170.8 (9.0)	33.9 (13.1)	0.01
Sugar, g	93.5 (5.5)	93.4 (5.0)	0.1 (7.5)	0.9	74.0 (5.7)	69.6 (7.0)	4.3 (10.3)	0.7	77.5 (4.8)	68.1 (4.5)	9.5 (6.6)	0.2	77.1 (4.6)	67.1 (4.3)	9.9 (6.3)	0.1
Fibers, g	16.8 (1.0)	16.9 (0.9)	−0.1 (1.4)	0.9	26.8 (1.4)	19.0 (1.3)	7.7 (1.9)	<.001	26.6 (1.5)	19.0 (1.4)	7.6 (2.1)	<.001	26.9 (1.5)	19.0 (1.4)	7.8 (2.0)	<.001
Proteins, g	83.9 (3.7)	80.2 (3.7)	3.8 (5.2)	0.5	43.4 (3.4)	63.6 (3.2)	−20.3 (4.6)	<.001	49.4 (2.8)	65.8 (2.7)	−16.4 (3.9)	<.001	50.2 (3.5)	66.2 (3.3)	−16.0 (4.8)	0.001
Alcohol, g	6.3 (2.2)	7.0 (2.2)	−0.6 (3.1)	0.8	3.1 (1.3)	4.0 (1.2)	−0.9 (1.8)	0.6	3.6 (1.9)	5.0 (1.8)	−1.3 (2.7)	0.6	4.7 (1.3)	3.7 (1.2)	1.1 (1.8)	0.6
Sodium, mg	3408 (146)	3542 (161)	−134 (220)	0.5	2386 (137)	2554 (129)	−168 (188)	0.4	2561 (108)	2695 (101)	−134 (148)	0.4	2626 (125)	2732 (118)	−106 (172)	0.5
Calcium, mg	776.4 (46.5)	822.0 (36.1)	−45.6 (58.2)	0.4	643.9 (43.2)	689.0 (40.6)	−45.1 (59.4)	0.4	694.1 (37.6)	681.6 (35.3)	12.5 (51.7)	0.8	811.1 (50.4)	699.3 (47.4)	111.8 (69.3)	0.1
Iron, mg	13.1 (0.7)	12.8 (0.6)	0.2 (0.9)	0.8	12.1 (0.6)	10.9 (0.6)	1.2 (0.8)	0.2	13.3 (0.8)	11.4 (0.7)	1.8 (1.1)	0.1	13.3 (0.9)	12.9 (0.8)	0.5 (1.2)	0.7
Nutrient Density
Total fat, % energy	37.8 (0.9)	37.6 (0.9)	0.1 (1.2)	0.9	29.5 (1.0)	34.2 (1.0)	−4.7 (1.4)	.001	30.7 (1.1)	35.6 (1.0)	−4.8 (1.5)	0.001	32.3 (1.2)	34.5 (1.1)	−2.2 (1.6)	0.2
Carbohydrates, % energy	43.8 (1.1)	45.0 (1.0)	−1.2 (1.5)	0.4	59.2 (1.3)	48.2 (1.2)	11.0 (1.8)	<.001	57.4 (1.3)	47.3 (1.2)	10.1 (1.8)	<.001	55.5 (1.5)	47.9 (1.4)	7.6 (2.1)	<.001
Proteins, % energy	17.7 (0.6)	16.4 (0.5)	1.3 (0.8)	0.1	13.6 (0.7)	18.5 (0.6)	−5.1 (0.9)	<.001	13.5 (0.6)	18.1 (0.6)	−4.7 (0.8)	<.001	13.3 (0.7)	18.8 (0.7)	−5.5 (1.0)	<.001
Sodium, mg/1000 kcal	1,779 (45.7)	1,811 (52.4)	−33 (70.4)	0.6	1,856 (74.3)	1,897 (69.8)	−41.3 (101.9)	0.7	1,792 (59.1)	1,873 (55.6)	−80.6 (81.2)	0.3	1,782 (62)	1,959 (59)	−177 (85.8)	0.04
Calcium, mg/1000 kcal	403.0 (17.9)	430.3 (17.6)	−27.3 (25.1)	0.3	498.1 (32.6)	530.3 (30.6)	−32.2 (44.8)	0.5	501.5 (25.4)	476.7 (23.9)	24.8 (35.0)	0.5	548.7 (26.8)	513.3 (25.2)	35.4 (36.8)	0.4
Iron, mg/1000 kcal	67.5 (2.4)	66.9 (2.8)	0.6 (3.7)	0.9	94.7 (4.9)	85.0 (4.6)	9.8 (6.7)	0.1	92.4 (4.8)	79.2 (4.6)	13.2 (6.7)	0.05	90.4 (5.0)	91.5 (4.7)	−1.1 (6.9)	0.9

¹Adjusted for baseline (month 0) consumption as a covariate in regression models.

Statistically significant (P<0.05) changes are bolded.

Abbreviations: diff, difference; g, grams; mg, milligrams; omni, omnivorous; SE, standard error

When we compared nutrient intake between those who were adherent to the vegan (n=32) and omnivorous (n=20) diet at 12 months, we found that the adherent vegan group had lower intake of cholesterol (mean difference ± SE: −85.4 ± 21.9 mg; P<0.001) and higher intake of fibers (mean difference ± SE: 8.4 ± 3.5 g; P=0.02), compared with the adherent omnivorous group (Table 3). Protein intake (% energy) was higher in the omnivorous group (mean difference ± SE: −5.1 ± 1.5 g; P=0.001). Comparing those who were non-adherent to the vegan (n=21) and omnivorous (n=40) diet at 12 months, those who were non-adherent to the vegan diet had lower intake of cholesterol (P<0.001) and proteins (P=0.02) and higher intake of carbohydrates (P=0.02), sugar (P=0.04), and fibers (P=0.01) (Table 4).

Table 3.

Nutritional intake¹ for adherent vegan and adherent omni at months 3, 6, and 12 among African Americans with overweight/obesity.

Macro- and Micronutrients	Month 3				Month 6				Month 12
	Adherent Vegan (n=32) (mean, SE)	Adherent Omni (n=20) (mean, SE)	Diff. (mean, SE)	P	Adherent Vegan (n=23) (mean, SE)	Adherent Omni (n=18) (mean, SE)	Diff. (mean, SE)	P	Adherent Vegan (n=27) (mean, SE)	Adherent Omni (n=21) (mean, SE)	Diff. (mean, SE)	P
Absolute Intake
Total energy, kcal/d	1322 (74)	1213 (94)	109 (120)	0.4	1461 (103)	1444 (116)	17 (156)	0.9	1547 (103)	1415 (116)	131 (156)	0.4
Total fat, g	43.9 (3.6)	46.6 (4.5)	−2.6 (5.8)	0.6	51.3 (5.9)	54.6 (6.7)	−3.3 (8.9)	0.7	60.6 (6.6)	51.9 (7.4)	8.7 (9.9)	0.4
Saturated fat, g	8.6 (1.0)	11.6 (1.2)	−3.1 (1.5)	0.05	10.1 (1.6)	14.4 (1.8)	−4.3 (2.5)	0.1	11.2 (1.5)	13.9 (1.7)	−2.7 (2.2)	0.2
Monounsaturated fat, g	16.1 (1.5)	17.2 (1.9)	−1.1 (2.4)	0.6	20.5 (2.6)	19.8 (2.9)	0.7 (3.9)	0.9	23.3 (3.0)	17.6 (3.4)	5.6 (4.6)	0.2
Polyunsaturated fat, g	15.8 (1.3)	13.9 (1.6)	1.9 (2.1)	0.4	16.8 (1.9)	15.7 (2.2)	1.1 (3.0)	0.7	21.5 (2.2)	16.0 (2.5)	5.6 (3.3)	0.1
Cholesterol, mg	18.6 (9.0)	105.3 (11.4)	−86.8 (14.8)	<.001	17.6 (24.4)	182.3 (27.6)	−164.7 (36.9)	<.001	35.1 (14.5)	120.5 (16.4)	−85.4 (21.9)	<.001
Carbohydrates, g	199.3 (10.5)	149.0 (13.3)	50.3 (16.9)	0.01	216.1 (13.1)	183.5 (14.9)	32.6 (20.0)	0.1	214.3 (13.5)	186.6 (15.4)	27.6 (20.7)	0.2
Sugar, g	75.7 (5.7)	54.7 (7.3)	21.0 (9.3)	0.03	73.2 (6.6)	69.6 (7.4)	3.7 (10.0)	0.7	78.3 (7.0)	75.1 (7.9)	3.1 (10.7)	0.8
Fibers, g	30.7 (2.0)	18.0 (2.6)	12.8 (3.3)	<.001	33.7 (2.7)	20.6 (3.1)	13.1 (4.1)	0.003	31.8 (2.3)	23.4 (2.7)	8.4 (3.5)	0.02
Proteins, g	40.9 (3.2)	49.3 (4.1)	−8.4 (5.3)	0.1	46.8 (4.4)	57.1 (5.0)	−10.3 (6.6)	0.1	47.7 (4.8)	61.4 (5.5)	−13.7 (7.3)	0.1
Alcohol, g	2.9 (1.8)	4.9 (2.3)	−2.0 (3.0)	0.5	1.2 (1.7)	4.4 (2.0)	−3.2 (2.6)	0.2	2.1 (0.9)	−0.1 (1.1)	2.3 (1.4)	0.1
Sodium, mg	2297 (155)	2152 (196)	145 (251)	0.6	2351 (169)	2624 (192)	−273 (256)	0.3	2678 (186)	2739 (211)	−61 (282)	0.8
Calcium, mg	712.4 (54.3)	610.4 (68.8)	102.0 (87.8)	0.3	740.6 (61.3)	682.2 (69.4)	58.4 (93.3)	0.5	837.8 (78.6)	743.2 (89.2)	94.6 (119.6)	0.4
Iron, mg	12.8 (0.7)	9.2 (0.9)	3.6 (1.1)	0.002	15.4 (1.4)	13.1 (1.6)	2.3 (2.2)	0.3	13.4 (1.4)	15.3 (1.6)	−1.9 (2.1)	0.4
Nutrient Density
Total fat, % energy	29.3 (1.4)	34.1 (1.8)	−4.7 (2.3)	0.05	29.2 (2.0)	34.5 (2.3)	−5.4 (3.0)	0.1	33.0 (2.0)	32.2 (2.2)	0.8 (3.0)	0.8
Carbohydrates, % energy	60.8 (1.7)	51.1 (2.2)	9.6 (2.8)	0.001	61.1 (2.1)	51.5 (2.4)	9.5 (3.2)	0.01	57.8 (2.0)	53.0 (2.3)	4.8 (3.1)	0.1
Proteins, % energy	12.7 (0.7)	15.9 (0.9)	−3.2 (1.1)	0.01	13.3 (0.8)	15.5 (0.9)	−2.2 (1.3)	0.1	12.5 (0.9)	17.6 (1.1)	−5.1 (1.5)	0.001
Sodium, mg/1000 kcal	1828 (110)	1798 (140)	30 (181)	0.9	1721 (102)	1843 (115)	−121 (154)	0.4	1834 (86)	1935 (97)	−101 (131)	0.4
Calcium, mg/1000 kcal	554.7 (53.7)	562.8 (68.0)	−8.0 (87.0)	0.9	571.7 (44.8)	479.5 (50.7)	92.2 (68.0)	0.2	562.9 (38.5)	544.4 (43.7)	18.5 (58.5)	0.8
Iron, mg/1000 kcal	100.5 (7.5)	87.1 (9.5)	13.4 (12.1)	0.3	110.2 (93	94.0 (10.6)	16.2 (14.3)	0.3	93.1 (8.5)	106.8 (9.7)	−13.7 (13.0)	0.3

¹Adjusted for baseline (month 0) consumption as a covariate in regression models.

Statistically significant (P<0.05) changes are bolded.

Abbreviations: diff, difference; g, grams; mg, milligrams; omni, omnivorous; SE, standard error

Table 4.

Nutritional intake¹ for non-adherent vegan and non-adherent omni at months 3, 6, and 12 among African Americans with overweight/obesity.

Macro- and Micronutrients	Month 3				Month 6				Month 12
	Non- adherent Vegan (n=21) (mean, SE)	Non- adherent Omni (n=40) (mean, SE)	Diff. (mean, SE)	P	Non- adherent Vegan (n=30) (mean, SE)	Non- adherent Omni (n=42) (mean, SE)	Diff. (mean, SE)	P	Non- adherent Vegan (n=26) (mean, SE)	Non- adherent Omni (n=39) (mean, SE)	Diff. (mean, SE)	P
Absolute Intake
Total energy, kcal/d	1354 (143)	1498 (1034)	−144 (177)	0.4	1499 (86)	1506 (73)	−8 (113)	0.9	1504 (102)	1447 (83)	57 (132)	0.7
Total fat, g	46.1 (5.6)	57.3 (4.1)	−11. 3 (6.90)	0.1	52.8 (3.5)	60.6 (3.0)	−7.8 (4.6)	0.1	53.6 (4.9)	57.7 (4.0)	−4.1 (6.4)	0.5
Saturated fat, g	11.4 (1.7)	15.1 (1.2)	−3.7 (2.1)	0.1	14.0 (1.0)	15.9 (0.9)	−1.8 (1.4)	0.2	14.7 (1.5)	16.4 (1.2)	−1.7 (1.9)	0.4
Monounsaturated fat, g	16.2 (2.3)	20.7 (1.7)	−4.6 (2.8)	0.1	18.1 (1.3)	21.9 (1.1)	−3.9 (1.7)	0.03	18.5 (1.9)	21.0 (1.5)	−2.5 (2.4)	0.3
Polyunsaturated fat, g	14.5 (1.7)	16.6 (1.2)	−2.1 (2.1)	0.3	16.2 (1.4)	18.0 (1.2)	−1.8 (1.8)	0.3	15.6 (1.6)	15.4 (1.3)	0.3 (2.1)	0.9
Cholesterol, mg	110.5 (28.9)	246.8 (20.9)	−136.2 (35.7)	<.001	104.9 (22.8)	231.8 (19.2)	−126 .9 (29.9)	<.001	114.0 (29.0)	265.7 (23.6)	−151.7 (37.4)	<.001
Carbohydrates, g	187.3 (22.6)	178.7 (16.4)	8.6 (28.0)	0.8	205.2 (11.3)	167.8 (9.6)	37.4 (14.9)	0.01	200.2 (13.1)	158.6 (10.7)	41.6 (17.0)	0.02
Sugar, g	71.9 (14.8)	76.8 (10.7)	−4.9 (18.3)	0.8	82.8 (6.4)	66.0 (5.4)	16.8 (8.4)	0.05	78.2 (6.2)	61.2 (5.1)	17.0 (8.1)	0.04
Fibers, g	21.1 (1.7)	19.4 (1.3)	1.8 (2.1)	0.4	21.4 (1.6)	18.2 (1.3)	3.2 (2.0)	0.1	22.1 (1.6)	16.4 (1.3)	5.7 (2.1)	0.01
Proteins, g	49.5 (5.9)	69.5 (4.3)	−20.0 (7.3)	0.01	51.5 (3.7)	69.3 (3.1)	−17.8 (4.8)	<.001	53.0 (5.1)	68.6 (4.2)	−15.6 (6.6)	0.02
Alcohol, g	3.1 (1.9)	3.7 (1.4)	−0.5 (2.3)	0.8	5.5 (3.0)	5.2 (2.6)	0.2 (4.0)	0.9	6.7 (2.3)	6.2 (1.9)	0.4 (3.0)	0.9
Sodium, mg	2561 (234)	2734 (169)	−173 (290)	0.6	2724 (140)	2723 (118)	2 (183)	0.9	2567 (172)	2731 (141)	−164 (222)	0.5
Calcium, mg	544.8 (68.6)	725.6 (49.5)	−180 .8 (84.9)	0.04	660.0 (48.7)	680.3 (41.1)	−20.3 (63.8)	0.8	793.7 (64.6)	668.7 (52.7)	125.0 (83.4)	0.1
Iron, mg	11.1 (1.0)	11.7 (0.7)	−0.6 (1.2)	0.6	11.7 (0.9)	10.7 (0.7)	1.0 (1.1)	0.4	13.3 (1.1)	11.6 (0.9)	1.7 (1.5)	0.2
Nutrient Density
Total fat, % energy	29.8 (1.6)	34.3 (1.1)	−4.5 (1.9)	0.02	32.0 (1.2)	36.1 (1.0)	−4.1 (1.6)	0.01	31.6 (1.4)	35.7 (1.2)	−4.1 (1.9)	0.03
Carbohydrates, % energy	56.8 (2.0)	46.8 (1.4)	10.0 (2.4)	<.001	54.6 (1.5)	45.4 (1.3)	9.2 (2.0)	<.001	53.3 (2.1)	44.9 (1.7)	8.4 (2.8)	0.004
Proteins, % energy	14.8 (1.2)	19.6 (0.9)	−4.9 (1.5)	0.002	13.9 (8)	19.1 (0.8)	−5.2 (1.1)	<.001	14.3 (1.1)	19.3 (0.9)	−5.0 (1.4)	0.001
Sodium, mg/1000 kcal	1914 (106)	1939 (76)	−25 (132)	0.8	1842 (73)	1889 (62)	−47 (96)	0.6	1725 (94)	1972 (76)	−247 (122)	0.05
Calcium, mg/1000 kcal	412.2 (34.1)	513.8 (24.7)	−101 .6 (42.3)	0.02	447.0 (29.2)	476.0 (24.7)	−29.0 (38.9)	0.5	534.5 (37.1)	496.1 (30.9)	38.4 (49.0)	0.4
Iron, mg/1000 kcal	86.7 (6.4)	83.5 (4.6)	3.2 (7.9)	0.7	77.7 (4.7)	73.6 (4.0)	4.0 (6.1)	0.5	88.4 (5.7)	82.8 (4.7)	5.5 (7.4)	0.5

¹Adjusted for baseline (month 0) consumption as a covariate in regression models.

Statistically significant (P<0.05) changes are bolded.

Abbreviations: diff, difference; g, grams; mg, milligrams; omni, omnivorous; SE, standard error

Adherence to AHEI-2010 and hPDI

Total AHEI-2010 and individual component scores by assigned intervention group are presented in Table 4. We found that the average AHEI-2010 score was consistently higher for participants assigned to the vegan diet intervention compared with those assigned to the omnivorous diet intervention (mean difference ± SE: 6.0 ± 2.1; P=0.01) at 12 months. Among the individual components, participants assigned to the vegan diet intervention had a healthier score for total vegetables (mean difference ± SE: 1.4 ± 0.4; P=0.001), red/processed meats (mean difference ± SE: 3.4 ± 0.7; P<0.001), and alcohol (mean difference ± SE: 0.9 ± 0.4; P=0.04) and less healthy score for long-chain fats (mean difference ± SE: −2.3 ± 0.7; P=0.002) compared with those assigned to the omnivorous diet intervention. Trends were consistent at months 3 and 6.

Total hPDI and individual component scores by assigned intervention group are presented in Table 5. The average hPDI score was consistently higher at 12 months for participants assigned to the vegan diet intervention compared with those assigned to the omnivorous diet intervention (mean difference ± SE: 6.7 ± 1.5; P<0.001). Of the individual components, participants assigned to the vegan diet intervention had a healthier score for vegetables (mean difference ± SE: 0.7 ± 0.3; P=0.004), fruits (mean difference ± SE: 0.6± 0.2; P=0.02), animal fat (mean difference ± SE: 0.6 ± 0.3; P=0.03), eggs (mean difference ± SE: 1.0 ± 0.3; P<0.001), fish or seafood (mean difference ± SE: 0.9 ± 0.3; P=0.01), and meat (mean difference ± SE: 1.6 ± 0.2; P<0.001) compared with participants assigned to the omnivorous diet intervention.

Table 5.

Total and component scores¹ for AHEI-2010² at months 0, 3, 6 and 12 among African Americans with overweight/obesity.

AHEI-2010 Components (0-10)	Month 0				Month 3				Month 6				Month 12
	Vegan (n=53) (mean, SE)	Omni (n=60) (mean, SE	Diff. (mean, SE)	P 3	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P
Total vegetables	3.8 (0.3)	4.1 (0.3)	−0.3 (0.4)	0.5	5.7 (0.3)	4.4 (0.3)	1.3 (0.4)	0.004	5.3 (0.3)	4.4 (0.3)	0.8 (0.5)	0.1	5.7 (0.3)	4.3 (0.3)	1.4 (0.4)	0.001
Total fruit	2.5 (0.3)	2.0 (0.2)	0.4 (0.4)	0.2	3.5 (0.3)	3.1 (0.3)	0.4 (0.5)	0.4	3.5 (0.3)	2.7 (0.3)	0.8 (0.4)	0.1	3.7 (0.3)	2.8 (0.3)	0.9 (0.4)	0.1
Whole grains	1.7 (0.3)	1.6 (0.2)	0.1 (0.3)	0.8	2.8 (0.3)	2.2 (0.3)	0.6 (0.4)	0.2	3.4 (0.3)	2.2 (0.3)	1.3 (0.4)	0.01	2.9 (0.3)	2.2 (0.3)	0.7 (0.5)	0.1
Nuts and legumes	6.0 (0.6)	5.3 (0.6)	0.7 (0.8)	0.4	8.1 (0.6)	6.5 (0.5)	1.6 (0.8)	0.04	7.7 (0.5)	6.8 (0.5)	0.9 (0.7)	0.2	7.7 (0.6)	6.8 (0.5)	0.8 (0.8)	0.3
Long-chain fats	4.5 (0.5)	4.8 (0.5)	−0.3 (0.7)	0.7	1.0 (0.4)	4.0 (0.4)	−3.0 (0.6)	<.001	1.4 (0.5)	4.0 (0.4)	−2.6 (0.7)	<.001	2.1 (0.5)	4.4 (0.5)	−2.3 (0.7)	0.002
Polyunsaturated fats	8.4 (0.3)	8.5 (0.2)	−0.1 (0.4)	0.7	8.5 (0.3)	8.6 (0.3)	−0.1 (0.4)	0.8	8.1 (0.3)	8.6 (0.3)	−0.5 (0.4)	0.2	8.4 (0.3)	8.1 (0.3)	0.3 (0.4)	0.4
Red/processed meat	3.4 (0.6)	5.0 (0.6)	−1.6 (0.9)	0.1	10.0 (0.5)	6.6 (0.4)	3.4 (0.6)	<.001	9.0 (0.5)	5.5 (0.5)	3.5 (0.7)	<.001	9.8 (0.5)	6.3 (0.5)	3.4 (0.7)	<.001
Sodium	4.9 (0.4)	5.2 (0.4)	−0.2 (0.5)	0.7	5.0 (0.4)	5.1 (0.4)	−0.1 (0.5)	0.8	4.8 (0.4)	5.3 (0.3)	−0.5 (0.5)	0.3	4.9 (0.4)	5.2 (0.4)	−0.4 (0.5)	0.5
Alcohol	3.0 (0.3)	2.8 (0.3)	0.2 (0.4)	0.7	3.1 (0.3)	3.0 (0.3)	0.1 (0.4)	0.7	3.3 (0.3)	2.5 (0.2)	0.8 (0.4)	0.03	3.6 (0.3)	2.8 (0.3)	0.9 (0.4)	0.04
AHEI-2010 (0-90)	38.2 (17)	39.3 (14)	−1.1 (2.1)	0.6	47.5 (14)	43.6 (13)	3.9 (11)	0.04	46.6 (13)	42.1 (13)	4.5 (18)	0.02	48.9 (11)	42.8 (15)	6.0 (24)	0.01

¹Adjusted for baseline consumption (month 0) as a covariate in regression models.

²Each component has a possible score of 0–10, with 0 being least healthy and 10 being healthiest.

³t-test used to test differences.

Statistically significant (P<0.05) changes are bolded.

Abbreviations: AHEI-2010, Alternative Healthy Eating Index 2010; diff, difference; omni, omnivorous; SE, standard error

DISCUSSION

The present study examined dietary adherence and differences in nutrient and food intake between a culturally adapted whole food, plant based vegan diet and a low-fat omnivorous diet among participants of the NEW Soul study. While both diets appeared to be reasonably acceptable ranging from 43-60% participants adherent for vegan diet and 30-35% participants adherent for omnivorous diet, we found higher adherence among participants assigned to the vegan diet.

Based on previous studies that used in-depth interviews and focus groups to examine the perspectives and experiences of participants in the NEW Soul study, we believe that factors that may have increased adherence include the cultural tailoring of recipes, partnering with local restaurants, and having AA facilitators in each class (26, 27). Additionally, self-efficacy may have played a prominent role in motivation and was created through mastery experiences, social persuasion, and positive psychological arousal (27).

Adherence to the vegan diet was highest at 3 months (60%) and remained moderately high at 12 months (51%). Adherence to the omnivorous diet was low across time (ranging from 30-35%). Previous studies have also found higher adherence to a vegan diet compared to an omnivorous diet (28-30). In a trial of 99 individuals with type 2 diabetes in a community-based setting of African Americans and whites, participants were randomly assigned to either a low-fat vegan diet or a diet based on the 2003 American Diabetes Association (ADA) guidelines for 74 weeks (28). At 22 weeks, 67% (33/49) of participants in the vegan group and 44% (22/50) of participants in the ADA diet group were considered adherent. In the New DIETs study, overweight and obese adults were randomized to one of four plant-based diets or an omnivorous diet. After 6 months, adherence to the vegan diet was 33% (4/12) and to the omnivorous diet was 17% (2/12) (29). Our results confirm our hypothesis that adherence and acceptability of a vegan diet may not be a major barrier among African Americans with overweight or obesity.

In line with previous studies, nutrient intake in the vegan diet group was lower in saturated fat and cholesterol and higher in fiber compared with the omnivorous diet. There are concerns of potential deficiency of some nutrients found in animal products such as protein, calcium, and iron (31). While we found that absolute and relative protein consumption was lower for the vegan group, nut and legume intake was higher compared to the omnivorous group. Protein intake has been found to be lower among individuals consuming plant-based diets compared to meat-eaters, though still within recommended intake levels and therefore not a major concern (32, 33). Relative fat intake was comparable between the groups, but there was a higher ratio of carbohydrates to proteins for the vegan group. Vegetarian and vegan diets tend to be high in carbohydrates; the source and type of carbohydrate is crucial to note given the different health effects. The vegan group scored higher for healthy sources of carbohydrates such as vegetables, fruits, and whole grains, but also scored slightly worse for refined grains. Therefore, while relative carbohydrate intake was higher in the vegan group, the sources included both healthy and unhealthy carbohydrates. While previous studies have found calcium intake to be lower among vegans and often below recommendations (31, 33), we did not find a difference in calcium intake between vegan adherent and omnivorous adherent groups. In Western diets, dairy is a major source of calcium intake. However, it is possible the vegan group obtained their calcium from alternative sources such as calcium-fortified orange juice, leafy greens, or almonds. The bioavailability of calcium from plant foods may be hindered from anti-nutrients such as lectins, oxalates, and phytates (34, 35). More research is warranted to determine how a vegan diet can provide adequate calcium intake. In our study, we found iron intake to be comparable between the two groups. Previous studies have found iron intake to be similar or higher in vegans compared with omnivores (32, 33). Many foods consumed in vegan diets such as green leafy vegetables, grains, and nuts and beans are rich in iron. However, sufficient iron intake is a concern for vegans as non-heme iron from plant foods have lower bioavailability compared to heme iron from animal meat (36). Therefore, vegans, especially women, are more likely to have iron deficiency (37).

At months 3, 6, and 12, the vegan intervention group had higher AHEI-2010 scores compared with the omnivorous group. The vegan group scored higher on vegetables, nuts and legumes, red/processed meat, and alcohol but poorer on long-chain fatty acids. Similarly, the vegan group scored higher on hPDI at months 3, 6, and 12, and performed better on vegetables, fruits, whole grains, legumes, animal fat, diary, eggs, fish or seafood, and meat, but performed worse on fruit juice. The AHEI-2010 and hPDI scores estimate adherence to an overall healthy dietary pattern, with the AHEI-2010 created to measure concordance with evidence-based recommendations to reduce risk of chronic disease and the hPDI created to reflect a healthful plant-based dietary pattern. Higher scores for both indices are associated with positive health outcomes including type 2 diabetes, cardiovascular disease, and all-cause mortality (2-4, 25, 38, 39). Previous studies have also found that vegan/vegetarian diets perform better on indices that measure adherence to healthy dietary patterns. Clarys et al. found that people following a vegan diet scored higher on the Healthy Eating Index 2010 (HEI-2010) and Mediterranean Diet Score compared to omnivores in a population of Belgian adults (31). In a systematic review, vegans scored higher on the HEI-2010 compared with nonvegetarians in 9 of 12 studies (40). Drivers of this difference mostly came from higher adherence to recommendations for total fruit, whole grains, seafood and plant protein, and sodium. Assessing overall dietary patterns offers a holistic view of the diet and accounts for interactions between foods and nutrients. Taken together, comparison between vegan and omnivorous groups in relation to individual nutrients, food groups, and dietary patterns all indicate that the vegan group had a healthy dietary profile and was sustained after 1 year.

This study was the first to our knowledge that used culturally adapted vegan and omnivorous dietary interventions among AAs. The incorporation of elements of soul food into the diets was a novel aspect to facilitate adoption of the diets in this population. Future studies that employ plant-based diets among an AA population might consider adding in culturally relevant soul foods to the intervention. The study utilized validated measures to assess dietary intake, through three unannounced 24-recalls (41). Additionally, the study was able to capture long-term dietary adherence and intake as data was collected at 12 months. Given that the first 6 months had more frequent in-person meetings compared to the next 6 months, the availability of data at the end of both time points allows us to evaluate sustainability, which has promising translational implications if the intervention is utilized in a real-world setting. Another strength of this study was the social support from chefs, dietitians, and other participants, which helped sustain participant motivation. Social support may be critical during dietary change, particularly among diets that may be novel (42). Further, a lack of social support has been associated with an inability to sustain a vegan diet (43).

A limitation of this study was the lack of dietary data collected on trans fats, sugar sweetened beverages, tea and coffee, and sweets and desserts. Because these data are not available as part of the output from ASA24, we modified the AHEI-2010 and hPDI scores to omit the components that were not present. Therefore, our scores have a smaller range and cannot be directly compared to the originally developed scores. Nonetheless, the scores still reflect a healthful dietary pattern, and we would expect the direction of results to be similar had those missing components been included. Another limitation is that this study was conducted among a population of AAs in the Midlands region of South Carolina. Therefore, generalizability is limited, and further research is warranted on AAs in other regions of the United States. However, the Southeast region of the United States has higher rates of obesity and hypertension as well as poorer diet quality (44), and is therefore a high priority region. In addition, only nutrient intake from food, but not supplements such as multivitamins, were included in the study. Both groups were provided with identical physical activity recommendations and in-class exercises; however, attempts to assess physical activity via accelerometers proved difficult, particularly during the COVID pandemic, so it is not known if exercise levels differed between groups. There were inherent differences in the dietary recommendations that may have made it easier, by design, for the vegan group to be considered adherent given they only had to avoid animal products while the omnivorous group had to eat within a specified range.

In conclusion, in a population of AA adults with overweight or obesity living in the southeastern US, those randomized to a culturally tailored vegan diet had significantly greater improvements in several key nutrients and diet quality as assessed by both the AHEI and hPDI as compared to those randomized to a culturally tailored omnivorous diet. In addition, adherence to the vegan diet prescribed in the study was higher than the prescribed omnivorous diet. While these results were over the course of one-year, additional research is warranted on even longer-term sustainability of adherence to a vegan dietary pattern and health outcomes.

Figure 1.

Participant flow diagram

Table 6.

Total and component scores¹ for hPDI² at months 0, 3, 6 and 12 among African Americans with overweight/obesity.

hPDI Components	Month 0				Month 3				Month 6				Month 12
	Vegan (n=53) (mean, SE)	Omni (n=60) (mean, SE)	Diff. (mean, SE)	P 3	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P	Vegan (mean, SE)	Omni (mean, SE)	Diff. (mean, SE)	P
Plant Food Groups
Healthy
Vegetables	2.9 (0.2)	3.1 (0.2)	−0.1 (0.3)	0.6	3.3 (0.2)	2.7 (0.2)	0.7 (0.2)	0.01	3.2 (0.2)	2.8 (0.2)	0.4 (0.3)	0.1	3.4 (0.2)	2.6 (0.2)	0.7 (0.3)	0.004
Fruits	3.1 (0.2)	2.9 (0.2)	0.2 (0.3)	0.4	3.1 (0.2)	2.9 (0.2)	0.2 (0.3)	0.5	3.2 (0.2)	2.8 (0.2)	0.5 (0.3)	0.1	3.3 (0.2)	2.7 (0.2)	0.6 (0.2)	0.02
Whole grains	3.0 (0.2)	2.8 (0.2)	0.2 (0.3)	0.5	3.2 (0.2)	2.8 (0.2)	0.4 (0.3)	0.1	3.3 (0.2)	2.7 (0.2)	0.6 (0.3)	0.02	3.2 (0.2)	2.8 (0.2)	0.4 (0.3)	0.1
Nuts	2.9 (0.2)	2.8 (0.2)	0.1 (0.3)	0.7	3.2 (0.2)	2.7 (0.2)	0.5 (0.3)	0.1	3.0 (0.2)	2.8 (0.2)	0.2 (0.3)	0.5	3.1 (0.2)	2.8 (0.2)	0.4 (0.3)	0.2
Legumes	2.6 (0.2)	2.1 (0.2)	0.5 (0.3)	0.2	3.1 (0.2)	2.3 (0.2)	0.8 (0.3)	0.01	3.0 (0.2)	2.6 (0.2)	0.4 (0.3)	0.2	2.8 (0.2)	2.5 (0.2)	0.3 (0.3)	0.3
Vegetable oils	3.0 (0.2)	3.0 (0.2)	0.03 (0.3)	0.9	3.0 (0.2)	3.0 (0.2)	0.02 (0.3)	0.9	3.1 (0.2)	2.9 (0.2)	0.1 (0.3)	0.6	3.2 (0.2)	2.8 (0.2)	0.5 (0.3)	0.1
Less healthy
Fruit juices	3.0 (0.2)	3.2 (0.2)	−0.2 (0.3)	0.6	3.1 (0.2)	3.6 (0.2)	−0.5 (0.3)	0.1	2.8 (0.2)	3.5 (0.2)	−0.7 (0.3)	0.01	3.2 (0.2)	3.4 (0.2)	−0.3 (0.3)	0.4
Refined grains	3.1 (0.2	3.0 (0.2)	0.1 (0.3)	0.6	3.0 (0.2)	3.0 (0.2)	0.02 (0.3)	0.9	3.0 (0.2)	3.0 (0.2)	−0.1 (0.2)	0.8	2.9 (0.2)	3.1 (0.2)	−0.2 (0.3)	0.4
Potatoes	3.2 (0.2)	2.9 (0.2)	0.3 (0.3)	0.2	3.0 (0.2)	3.5 (0.2)	−0.5 (0.3)	0.1	3.2 (0.2)	3.1 (0.2)	0.1 (0.3)	0.8	3.2 (0.2)	3.3 (0.2)	−0.1 (0.3)	0.7
Animal Food Groups
Animal fat	3.1 (0.2)	3.0 (0.2)	0.1 (0.3)	0.6	3.4 (0.2)	2.7 (0.2)	0.8 (0.2)	0.002	3.3 (0.2)	2.7 (0.2)	0.6 (0.2)	0.02	3.3 (0.2)	2.7 (0.2)	0.6 (0.3)	0.03
Dairy	3.4 (0.2)	2.7 (0.2)	0.6 (0.3)	0.02	3.4 (0.2)	2.6 (0.2)	0.8 (0.3)	0.003	3.3 (0.2)	2.7 (0.2)	0.6 (0.3)	0.02	3.3 (0.2)	2.8 (0.2)	0.5 (0.3)	0.05
Eggs	3.0 (0.2)	3.1 (0.2)	−0.1 (0.3)	0.8	3.7 (0.2)	2.5 (0.2)	1.3 (0.2)	<.001	3.5 (0.2)	2.6 (0.2)	0.9 (0.3)	0.001	3.6 (0.2)	2.5 (0.2)	1.0 (0.3)	<.001
Fish or Seafood	3.3 (0.3)	3.3 (0.2)	−0.1 (0.3)	0.8	4.5 (0.2)	3.3 (0.2)	1.2 (0.3)	<.001	4.4 (0.2)	3.2 (0.2)	1.2 (0.3)	<.001	4.1 (0.2)	3.2 (0.2)	0.9 (0.3)	0.01
Meat	2.8 (0.2)	3.2 (0.2)	−0.4 (0.3)	0.2	4.2 (0.2)	2.2 (0.2)	2.0 (0.2)	<.001	4.0 (0.1)	2.2 (0.1)	1.8 (0.2)	<.001	4.0 (0.2)	2.3 (0.2)	1.6 (0.2)	<.001
hPDI score (14-70)	42.4 (1.0)	40.9 (0.9)	1.5 (1.4)	0.3	47.2 (1.0)	39.8 (0.9)	7.4 (1.3)	<.001	46.2 (1.1)	39.9 (1.0)	6.2 (1.5)	<.001	46.4 (1.1)	39.7 (1.0)	6.7 (1.5)	<.001

¹Adjusted for baseline (month 0) consumption as a covariate in regression models.

²Each component has a possible score of 1-5, with 1 being least healthy and 5 being healthiest. Participants are ranked 1-5 based on quintile of consumption. For healthy components, participants in quintile 5 received a score of 5. For unhealthy components, participants in quintile 5 received a score of 1.

³t-test used to test whether difference was statistically significant.

Statistically significant (P<0.05) changes are bolded.

Abbreviations: diff, difference; hPDI, healthy plant-based diet index; omni, omnivorous; SE, standard error

Abbreviations:

AAs

African Americans

AHEI-2010

Alternative Healthy Eating Index 2010

ASA24

Automated Self-administered 24-hour recall

CVD

cardiovascular disease

hPDI

healthy plant-based diet index

Omni

omnivorous

NEW Soul

Nutritious Eating with Soul