The Dietary Guidelines 3 Diets Study

NCT ID: NCT04981847

Last Updated: 2026-01-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 63 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-08-01
• Study Completion Date: 2025-06-23

Brief Summary

The goal of this project is to use a two-stepped study to examine both the adoption of the three dietary patterns as presented by the United States Dietary Guidelines (USDG) and testing of a refined, culturally tailored one-year intervention examining the three diet patterns. For this study, African American adult participants with overweight/obesity and ≥three type 2 diabetes (T2DM) risk factors will be recruited to participate in this two-step study. This present study is for our Step 1: formative pilot work to culturally-tailor a dietary intervention of the three healthy eating patterns presented by the USDG for 12 weeks: 1) U.S.-Style, 2) Mediterranean, or 3) Vegetarian.

Detailed Description

The U.S. Dietary Guidelines (USDG) form the basis of federal nutrition programs and policy and provide valuable guidance to health initiatives and industries. The updated 2015 USDG moved away from a focus on individual nutrients to a greater focus on dietary patterns. The USDG state that healthy eating goals can be met through a variety of dietary patterns, but present healthy diet in three main ways: 1) Healthy U.S.-Style Eating Pattern, 2) Healthy Mediterranean-Style Eating Pattern, and 3) Healthy Vegetarian Eating Pattern. Currently, US adults are falling short of the nutrition recommendations (fruit/vegetable intake, greens/beans, whole grains, etc.) set forth by the USDG and measured by the Healthy Eating Index (HEI). While the USDG are the basis of nutrition guidelines, the research informing these dietary pattern recommendations has largely been drawn from observational studies among mostly white populations. In addition, there has been very limited cultural tailoring of these dietary patterns that would ensure that these diets are acceptable to diverse populations, in particular, African Americans (AAs) living in the south, who experience a disproportionate burden of chronic disease, especially type 2 diabetes (T2DM). Currently, US adults are not meeting nutrition recommendations (fruit/vegetable, whole grains, etc.) set forth by the USDG and measured by the Healthy Eating Index (HEI).

For the present study, AA adult participants with overweight/obesity and ≥three T2DM risk factors will be recruited to participate in the following aims:

Aim 1: Conduct a 3-month randomized trial among AAs comparing adoption of the 3 dietary patterns [1) US, 2) Med, or 3) Veg] using existing materials from the USDG and examine differences in diet quality (HEI) and T2DM risk factors (weight, HgbA1c).

Aim 2: Drawing on participants' experiences in Aim 1, conduct qualitative work to refine and culturally tailor the dietary pattern intervention for an AA audience.

Conditions

Type 2 Diabetes

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: SINGLE

Study Groups

US Healthy Diet

Participants in this group will be assigned to follow the Healthy US dietary pattern as presented by the US Dietary Guidelines. As described here https://www.nia.nih.gov/health/usda-food-patterns: This eating pattern is based on the types and amounts of foods Americans typically consume. The main types of food in this eating pattern include a variety of vegetables; fruits; whole grains; fat-free or low-fat dairy; seafood, poultry, meat, and eggs; and nuts, seeds, and soy products.

Group Type: EXPERIMENTAL

Dietary Intervention Meetings

Intervention Type: BEHAVIORAL

Participants will attend classes once per week for 3 months.

Mediterranean diet

Participants in this group will be assigned to follow the Mediterranean dietary pattern as presented by the US Dietary Guidelines. As described here https://www.nia.nih.gov/health/usda-food-patterns: This eating pattern contains more fruits and seafood and less dairy than the Healthy U.S.-Style Eating Pattern. There is also less calcium and vitamin D because it includes fewer dairy foods.

Group Type: EXPERIMENTAL

Dietary Intervention Meetings

Intervention Type: BEHAVIORAL

Participants will attend classes once per week for 3 months.

Vegetarian diet

Participants in this group will be assigned to follow the Vegetarian dietary pattern as presented by the US Dietary Guidelines. As described here https://www.nia.nih.gov/health/usda-food-patterns: This eating pattern contains no meat, poultry, or seafood. Compared with the Healthy U.S.-Style Eating Pattern, it contains more soy products, eggs, beans and peas, nuts and seeds, and whole grains.

Group Type: EXPERIMENTAL

Dietary Intervention Meetings

Intervention Type: BEHAVIORAL

Participants will attend classes once per week for 3 months.

Interventions

Dietary Intervention Meetings

Participants will attend classes once per week for 3 months.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• 18-65 years of age
• BMI between 25- 49.9 kg/m2
• self-identify as African American
• live in the Columbia, SC area
• be able to attend all monitoring visits
• be willing to be randomized to either condition and be re-randomized if non-responsive
• be free of major health or psychiatric diseases, drug or alcohol dependency, thyroid conditions, diabetes, or pregnancy

Exclusion Criteria

• should not be pregnant (or have been pregnant in the last 6 months), anticipating on becoming pregnant in the next 24 months, or currently breastfeeding

o Women who are pregnant should not be pursuing weight loss and should be under the direct care of a physician. Therefore women who are pregnant or who are anticipating they might be pregnant should not participate in this study. If a woman becomes pregnant during the study, she will be advised to consult with her healthcare provider and will be dropped from the weight loss study.

• should be free of an eating disorder as screened by the Eating disorder Screen for Primary care [ESP]. (If a participant has an eating disorder, they will be given contact information for the eating disorder clinic at the University of South Carolina)
• no current participation in a weight loss program or taking weight loss medications (although participants may be trying to lose weight on their own)
• no recent or planned bariatric surgery
• no recent weight loss (>10 lbs in the last 6 months)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of South Carolina

OTHER

Sponsor Role: lead

Responsible Party

Brie Turner-McGrievy

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University of South Carolina

Columbia, South Carolina, United States

Countries

United States

References

Turner-McGrievy G, Wirth MD, Okpara N, Jones M, Kim Y, Wilcox S, Friedman DB, Sarzynski MA, Liese AD. Similar changes in diet quality indices, but not nutrients, among African American participants randomized to follow one of the three dietary patterns of the US Dietary Guidelines: A secondary analysis. Nutr Res. 2024 Nov;131:27-38. doi: 10.1016/j.nutres.2024.09.005. Epub 2024 Sep 7.

Reference Type: DERIVED

PMID: 39366028 (View on PubMed)

Turner-McGrievy GM, Wilson MJ, Carswell J, Okpara N, Aydin H, Bailey S, Davey M, Hutto B, Wilcox S, Friedman DB, Sarzynski MA, Liese AD. A 12-Week Randomized Intervention Comparing the Healthy US, Mediterranean, and Vegetarian Dietary Patterns of the US Dietary Guidelines for Changes in Body Weight, Hemoglobin A1c, Blood Pressure, and Dietary Quality among African American Adults. J Nutr. 2023 Feb;153(2):579-587. doi: 10.1016/j.tjnut.2022.11.020. Epub 2022 Dec 23.

Reference Type: DERIVED

PMID: 36894249 (View on PubMed)

Other Identifiers

Pro00105836

Identifier Type: -

Identifier Source: org_study_id