Background
The US Dietary Guidelines (USDG) form the basis of nutrition guidelines, but the research informing the 3 USDG dietary patterns (Healthy US-Style [H-US], Mediterranean [Med], and vegetarian [Veg]) has been drawn largely from observational studies among White populations.
Methods
The AAs (ages 18–65 y, BMI 25–49.9 kg/m2, and BMI was measured in kg/m2) with ≥3 type 2 diabetes mellitus risk factors were recruited. Weight, HbA1c, blood pressure, and dietary quality (healthy eating index [HEI]) were collected at baseline and 12 wk. In addition, participants attended weekly online classes that were designed using material from the USDG/MyPlate. Repeated measures, mixed models with maximum likelihood estimation, and robust computation of standard errors were tested.
Results
Of the 227 participants screened, 63 were eligible (83% female; age 48.0 ± 10.6 y, BMI 35.9 ± 0.8 kg/m2) and randomly assigned to the Healthy US-Style Eating Pattern (H-US) (n = 21, 81% completion), healthy Mediterranean-style eating pattern (Med) (n = 22, 86% completion), or healthy vegetarian eating pattern (Veg) (n = 20, 70% completion) groups. Within-group, but not between groups, weight loss was significant (−2.4 ± 0.7 kg H-US, −2.6 ± 0.7 kg Med, −2.4 ± 0.8 kg Veg; P = 0.97 between group). There was also no significant difference between groups for changes in HbA1c (0.03 ± 0.05% H-US, −0.10 ± 0.05% Med, 0.07 ± 0.06% Veg; P = 0.10), systolic BP (−5.5 ± 2.7 mmHg H-US, −3.2 ± 2.5 mmHg Med, −2.4 ± 2.9 mmHg Veg; P = 0.70), diastolic blood pressure (−5.2 ± 1.8 mmHg H-US, −2.0 ± 1.7 mmHg Med, −3.4 ± 1.9 mmHg Veg; P = 0.41), or HEI (7.1 ± 3.2 H-US, 15.2 ± 3.1 Med, 4.6 ± 3.4 Veg; P = 0.06). Post hoc analyses showed that the Med group had significantly greater improvements in HEI compared to the Veg group (difference = −10.6 ± 4.6; 95% CI: −19.7, −1.4; P = 0.02).