Healthy vegan or low-fat omnivorous soul food diets yield no significant differences in weight loss or lipid and blood pressure levels among African American adults, according to a randomized clinical trial published in JAMA Network Open.

“Although several studies have found evidence suggesting that plant-based diets may be protective against CVD, most have been observational. The few interventions examining plant-based diets have found that they have the potential to reduce factors associated with risk of cardiovascular disease, such as trimethylamine-N-oxide, C-reactive protein and LDL cholesterol,” Gabrielle M. Turner-McGrievy, PhD, RD,professor in thedepartment of health promotion, education and behavior and the Prevention Research Center at the Arnold School of Public Health at the University of South Carolina, and colleagues wrote. “African American vegetarians and vegans have significantly lower risks of hypertension, diabetes and elevated cholesterol than African American omnivores.”

The Nutritious Eating with Soul study, a randomized, 2-year clinical trial of two cohorts from 2018-2020 and 2019-2020, included 159 African American adults with overweight or obesity (mean age, 48.4 years; 79% women) from a university teaching kitchen in Columbia, South Carolina, prior to the COVID-19 pandemic and via online videoconference sessions following COVID-19. Participants received weekly nutrition classes for 6 months, biweekly classes for 6 months and monthly classes for 12 months.

All participants were randomly assigned to a dietary intervention emphasizing a vegan diet with no animal product consumption (n = 77) or a low-fat omnivorous diet (n = 82), with both diets emphasizing soul food cuisine.

The primary outcomes were change in body weight and lipid levels at 12 months.

Overall, 76% of participants had data for the primary outcome at the conclusion of the study. Researchers observed no differences between the vegan diet group and the omnivore diet group for weight (–2.39 vs. –2.03 kg), total cholesterol (–1.05 vs. 1.66 mg/dL) or LDL cholesterol (–2.56 vs. –0.79 mg/dL).

At 12 months, the first cohort — wherein weight was assessed prior to the COVID-19 pandemic — experienced greater weight loss compared with the second cohort, whose weight was assessed during the pandemic (–3.45 vs. –1.24 kg; P = .01).

“Future research should examine additional strategies to enhance adherence to [plant-based diets], such as testing the intervention in a non-university, community-based setting or providing ready-to-eat meals,” the researchers wrote.