Whole Food for Families: A Pilot RCT of a Dietary Guidelines-Based Intervention to Prevent Type 2 Diabetes

NCT ID: NCT06482944

Last Updated: 2025-10-21

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-10-13
• Study Completion Date: 2027-06-30

Brief Summary

This study will address the following aims:

Aim 1 (primary): Conduct a pilot RCT to evaluate the feasibility, acceptability, enrollment, and retention rates of adult-child pairs after a 12-week family-centered, non-calorie restricted whole foods diet.

Feasibility: ≥80% participant retention and completion of study outcome measures.

Acceptability: ≥75 adult diet satisfaction via survey report and/or perceived diet satisfaction via focus groups. Aim 2: Conduct a pilot RCT to evaluate the preliminary effectiveness of a non-calorie restricted whole foods diet on adult HbA1c at 12 weeks and adult/child diet quality during the 12-week intervention.

Aim 2a: Evaluate intervention effects on HbA1c measures in adults with prediabetes.

Hypothesis 2a: Adults randomized to the treatment group will have lower HbA1c measures at 12 weeks than those in the control group.

Aim 2b: Evaluate intervention effects on the diet quality (via the 2020 HEI) of adults and children. Hypothesis 2b: Adults and children randomized to the treatment group will have a higher diet quality score during the 12-week intervention period compared to adults and children in the control group.

Aim 3: Conduct family focus groups to understand how SDOH and individual/family needs and preferences may be perceived barriers or facilitators of diet adherence.

Detailed Description

This dietary program is based on empirical evidence showing that a diet pattern that favors minimally processed and whole foods (e.g., whole grains, fruits, vegetables, nuts) in contrast to diet patterns with greater consumption of highly refined and ultra-processed foods are attributed to greater reductions in HbA1c and fasting plasma glucose and a reduced risk for T2D. This evidence comes primarily from prospective cohort and clinical studies of 1) adult populations without diabetes (including type 2 and pre-diabetes) and 2) adult populations with active T2D. Studies of family dietary interventions for transgenerational T2D prevention are lacking.

Studies have focused primarily on structured diet patterns such as the Mediterranean style, Vegetarian or Vegan, Dietary Approaches to Stop Hypertension (DASH), carbohydrate-restricted, and low-fat. Evidence supports that the diet patterns most effective for T2D risk reduction focused on primarily whole food consumption (e.g., Mediterranean-style, Vegetarian, and DASH). Yet, less attention has been given to studying the effectiveness of the Dietary Guidelines for American's (DGA) diet pattern which forms the basis of nutrition advice in the U.S. and is the guiding nutrition framework used for federal nutrition policy. Moreover, a benefit of the recent DGA is its customizable approach to diet.

Recognizing the importance of a whole foods structured diet and the recent shift of the Dietary Guidelines for American's DGA diet pattern towards a customizable, family-centered, whole foods approach, studies that test the effectiveness of a DGA-structured diet for T2D risk reduction should be prioritized. Before conducting efficacy and effectiveness trails, pilot data is needed to determine the feasibility and acceptability of using this family- centered diet approach in a population at "high risk" for T2D. Applying a family- lens where a transgenerational approach can be used to prevent T2D is necessary.

Therefore, this program aims are to test the feasibility and acceptability of delivering a whole foods diet pattern using a family centered approach in a population at risk for T2D- adults with prediabetes and their "at-risk" biological offspring. This study will also test the preliminary effectiveness on the diet's effects on change in adult hemoglobin A1c at 12 months and will assess changes in diet quality during the intervention in adults and offspring.

Conditions

PreDiabetes; Diet, Healthy; Nutritional and Metabolic Diseases

Study Design

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

Study Groups

Whole Foods Counseling Group (Control)

Participants randomized to the control group will receive dietetic counseling sessions (weeks 1-2) on the 2020-2025 Dietary Guidelines for Americans (DGA) which is considered a healthy diet pattern for prediabetes. Diet adherence will be assessed with 3-day food diary in weeks 1-12. Study personnel and/or the study RDN will follow up with the participants during the study to review the food diaries.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Whole Foods Healthy Eating Group (Intervention)

The 12-week whole foods intervention consists of 2 phases. The feeding phase (weeks 1-8) is comprised of an intensive 2-week controlled feeding period followed by a 6-week partial feeding period. This diet intervention will encourage the consumption of a whole foods "dietary pattern". The maintenance phase (weeks 9-12) is a 4-week "free-living" period to assess intervention feasibility without food provision or dietetic support.

Group Type: EXPERIMENTAL

Whole Foods for Families

Intervention Type: BEHAVIORAL

This diet intervention will encourage the consumption of a whole foods "dietary patterns" such as a wide variety of fruits, vegetables, proteins, seafood, dairy and whole grains. During the partial feeding period (weeks 3-8), families will be asked to continue the whole foods diet with support that includes: 1) 3 weekly dinners of the families' choosing (described above), 2) rotating menus (\~3 weeks' worth) that will allow for customization (e.g., protein, vegetable, grain swaps) to support cultural/dietary preferences, and 3) dietetic support to help with customization and diet maintenance. Participants will be instructed by the registered dietitian nutritionist (RDN) on how to adhere to the diet intervention and will be provided menus and recipes. For the enrolled families in the study, the goal is to maintain complete diet adherence during the twelve-week intervention.

Interventions

Whole Foods for Families

This diet intervention will encourage the consumption of a whole foods "dietary patterns" such as a wide variety of fruits, vegetables, proteins, seafood, dairy and whole grains. During the partial feeding period (weeks 3-8), families will be asked to continue the whole foods diet with support that includes: 1) 3 weekly dinners of the families' choosing (described above), 2) rotating menus (\~3 weeks' worth) that will allow for customization (e.g., protein, vegetable, grain swaps) to support cultural/dietary preferences, and 3) dietetic support to help with customization and diet maintenance. Participants will be instructed by the registered dietitian nutritionist (RDN) on how to adhere to the diet intervention and will be provided menus and recipes. For the enrolled families in the study, the goal is to maintain complete diet adherence during the twelve-week intervention.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

For this study, eligible adults will be those that:

1. are 25 to 59 years of age at time of initial screen and identify as a parent to at least one child or adolescent 6-18 years;

2. have a body mass index of between ≥23kg/m2 to <40kg/m2;

3. have prediabetes (based on American Diabetes Association criteria of either fasting plasma glucose of ≥100 mg/dL, HgbA1c 5.7-6.4%, or 2-hour plasma glucose during 75-g oral glucose tolerance test [OGTT] 140 mg/dL to 199 mg/dL) with recent lab values reported within the prior 6-12 months and confirmed by an HbA1c A1cNow+ collected prior to enrollment (*see comment below);

4. have no special dietary restrictions or food allergies that would prohibit consumption of a variety of foods/beverages;

5. are English speaking;

6. reside in Greater Nashville Tennessee and willing to come to Vanderbilt campus and Vanderbilt University Medical Center for required study visits;

7. are without medical conditions that would limit participation in a diet-related study (e.g., tube feeding, dysphagia, severe food allergy causing anaphylaxis);

8. are able to participate in a 12-week dietary program that requires home preparation/cooking for meals and snacks;

For this study, eligible offspring will be those that:

1. Are 6-18 years at time of initial screen;

2. Have an index parent with prediabetes that is actively enrolled in the program;

3. have body mass index ≥5th percentile for age and gender on standardized CDC growth curves;

4. have no special dietary restrictions or food allergies that would prohibit consumption of a variety of foods/beverages;

5. have parental commitment to participate in a 12-week research study

6. are English speaking;

7. reside in the Greater Nashville Tennessee area and live at home with their index parent during the duration of 12- week study;

8. are without medical conditions that would limit participation in a diet-related study (e.g., tube feeding, dysphagia, severe food allergy causing anaphylaxis);

9. are able to participate in a 12-week dietary program that includes at least dinner and snacks provided during after-school hours;

Exclusion Criteria

1. Adults who's HbA1c test is outside of the HbA1c range during screening* (see details related to screening results)

2. adults outside the specified age range of <25 years or >59 years;

3. adults whose body mass index is <23kg/m2 or those with a body mass index ≥40kg/m2 as that degree of morbid obesity represents a different phenotype where dietary behavioral intervention alone may not be sufficient to achieve weight loss);

4. receiving care by a healthcare provider (i.e., MD, NP, PA) for a complicated diagnosis of prediabetes that requires routine glycemic monitoring or frequent healthcare visits for management/treatment;

5. adults actively participating in any type of weight loss program (dietary or physical activity)

6. adults with a prior history of type 2 diabetes;

7. adults who are not English speaking or have limited English-language proficiency;

8. adults with special dietary restrictions, food allergies, or medical conditions that prohibit participation in a diet-related study;

9. adults with serious mental or neurologic illness that impairs the ability to consent/participate;

10. women who are pregnant or nursing due to increased metabolic state requiring greater energy requirements;

11. adults currently taking medications to treat diabetes or to promote weight loss;

12. adults living outside Greater Nashville Tennessee or who are unwilling to travel to Vanderbilt for study visits;

13. adults who do not otherwise meet the eligibility criteria listed in sections above as determined by pre-screen;

1. children/adolescents outside the specified age range of <6 years or >18 years;

2. children/adolescents whose body mass index is <5th percentile for age and gender on standardized CDC growth curves;

3. children/adolescents who do not have an eligible index parent participating in the study;

4. children who do not have parental commitment to participate consistently for 12-weeks

5. children/adolescents who are not English speaking or have limited English-language proficiency;

6. children/adolescents with special dietary restrictions, food allergies, or medical conditions that prohibit participation in a diet-related study;

7. children/adolescents who display dissenting behaviors during baseline data collection;

8. children/adolescents actively participating in any type of weight loss program (medical or lifestyle);

9. children/adolescents who do not otherwise meet the eligibility criteria listed in sections above as determined by pre-screen;

• Minimum Eligible Age: 6 Years
• Maximum Eligible Age: 59 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Vanderbilt University Medical Center

OTHER

Sponsor Role: collaborator

Vanderbilt University

OTHER

Sponsor Role: lead

Responsible Party

Nadia Markie Sneed

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Nadia M Sneed, PhD, MSN

Role: PRINCIPAL_INVESTIGATOR

Vanderbilt University

Locations

Vanderbilt University School of Nursing

Nashville, Tennessee, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Nadia M. Sneed, PhD, MSN

Role: CONTACT

nadia.sneed@vanderbilt.edu

615-343-1542

Kylee Vecchi, MS

Role: CONTACT

Facility Contacts

Bryn Evans, MMHC, PMP

Role: primary

bryn.evans@vanderbilt.edu

615-343-3290

Gay Nell Krauss, MPA, CRA

Role: backup

gaynell.krauss@Vanderbilt.Edu

615-343 6070

Provided Documents

Document Type: Informed Consent Form

View Document

Other Identifiers

240761

Identifier Type: -

Identifier Source: org_study_id