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NCT Number: NCT04293224

Metabolic and Bio-behavioral Effects of Following Recommendations in the Dietary Guidelines for Americans

This study, at the Western Human Nutrition Research Center (WHNRC), will focus on whether or not achieving and maintaining a healthy body weight is the most important health promoting recommendation of the Dietary Guidelines for Americans (DGA).The investigators hypothesize that improvement in cardiometabolic risk factors resulting from eating a DGA style diet will be greater in people whose energy intake is restricted to result in weight loss compared to those who maintain their weight. The investigators further propose that during a state of energy restriction, a higher nutrient quality diet such as the DGA style diet pattern, will result in greater improvement in cardiometabolic risk factors compared to a typical American diet (TAD) pattern that tends to be lower nutrient quality (more energy-dense and less nutrient-rich.)

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Key information

Conditions

Obesity Behavior Behavior, Animal Body Weight Cardiovascular Diseases Diabetes Mellitus Endocrine System Diseases Feeding Behavior Glucose Intolerance Glucose Metabolism Disorders Hyperglycemia Hyperinsulinism Insulin Resistance Metabolic Diseases Metabolic Syndrome Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Prediabetic State Prehypertension Signs and Symptoms Vascular Diseases

Age range

19 year–64 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

UC Davis, Western Human Nutrition Research Center

Davis, California, 95616, United States

Location status: Recruiting

About this study

This will be a 28-week study including pre-diet testing (week 1), an 8-week controlled feeding period, post-diet testing (week 10), a follow-up period of dietary education and observation, and end of study testing (week 28). During the 8 week feeding, participants will be randomly assigned one of the following diets:

  • DGA Mediterranean diet pattern at sufficient energy level to maintain body weight (energy balance)
  • DGA Mediterranean diet pattern at a moderately reduced energy level (negative energy balance)
  • TAD diet pattern at a moderately reduced energy level (negative energy balance)

In the follow-up phase, the investigators will evaluate how multiple factors may influence body weight management, including previous dietary exposure, as well as the role of cognitive function, executive function, genetics, habitual diet, physical activity, eating behavior, stress and stress responsivity, metabolic flexibility and gut microbiome.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Body Mass Index (BMI) 23-39.9 kg/m2 or 32-50% body fat percentage
  • Willingness to have blood drawn
  • The criteria listed above and at least one of the following: Fasting glucose ≥100 mg/dL but <126 mg/dL or Fasting triglyceride ≥125 mg/dL or HDL-cholesterol ≤50 mg/dL or Blood Pressure (BP): Systolic BP ≥130 mmHg or Diastolic BP ≥85 mmHg or Hemoglobin A1C ≥ 5.7 and <6.5%

Exclusion criteria

  • Active participation in another research study
  • Tested positive for COVID-19 within the past 10 days
  • Been in close contact with a COVID-19 positive person within the past 14 days
  • Blood Pressure (BP): Systolic BP ≥140 mmHg or Diastolic BP ≥90 mmHg
  • LDL cholesterol ≥190 mg/dL
  • Triglycerides ≥500 mg/dL
  • Current use of smoking or chewing tobacco, e-cigarettes, cigars, vaping, cannabis or other use of nicotine containing products (within the past 6 months)
  • Current use of dietary supplements and/or unwillingness to cease intake of dietary supplements
  • Vegan or vegetarian lifestyle or any other dietary restrictions that would interfere with consuming the intervention foods and beverages (including dietary intolerances, allergies and sensitivities)
  • Unwillingness to consume intervention foods and beverages
  • Engage in more than moderate drinking (> 1 drink serving per day) or binge drinking (4 drinks within two hours).
  • Unwillingness to cease alcohol intake as required for specific duration of the study
  • Excessive intake of caffeine containing products (excessive defined as ≥ 400 mg/day)
  • Unwillingness to refrain from caffeine intake on lab visit days.
  • Intentional weight change of ≥5% of body weight within 6 months of entry into the study
  • Diagnosis of disordered eating or eating disorder
  • Recent diagnosis of any of the following or measurement on screening lab tests: Anemia (hemoglobin <11.7 g/dL) or abnormal liver or thyroid function (defined as liver enzymes that are >200% of upper limit (ALT upper limit is 43 U/L or Aspartate transaminase (AST) upper limit is 54 U/L) and thyroid function tests: Thyroxine (T4, free) <0.56 or >1.64 ng/dL; Thyroid-stimulating hormone (TSH) <0.35 or >5.6 μIU/mL).
  • History of any of the following: Gastric bypass surgery, inflammatory bowel disease (IBD) or other GI conditions that would interfere with consuming the intervention foods, active cancer in the past three years excluding squamous or basal cell carcinomas of the skin that have been handled medically by local excision and other serious medical conditions
  • Recent dental work or have conditions of the oral cavity that would interfere with consuming the intervention foods and beverages
  • Taking any medication in the class of antipsychotics
  • Long term use of antibiotics
  • Taking any over the counter or prescribed medication for any of the following: Elevated lipids, elevated glucose, high blood pressure, weight loss or conditions that require corticosteroids (e.g. asthma, arthritis or eczema).
  • Are pregnant, planning to become pregnant within the duration of the study or breastfeeding.

Treatment and study plan

DGA Mediterranean diet pattern, energy balance

Other

Foods and beverages will be provided for participants for eight weeks. During the controlled feeding portion of the study the DGA Mediterranean diet pattern will be based on the Table A7-1 of the 2015 Dietary Guidelines for Americans which outlines daily nutritional goals for age-sex groups based on Dietary Reference Intakes (DRI) and dietary guidelines recommendations.

DGA Mediterranean diet pattern, negative energy balance

Other

Foods and beverages will be provided for participants for eight weeks. During the controlled feeding portion of the study the DGA Mediterranean diet pattern will be based on the Table A7-1 of the 2015 Dietary Guidelines for Americans which outlines daily nutritional goals for age-sex groups based on Dietary Reference Intakes (DRI) and dietary guidelines recommendations

TAD diet pattern, negative energy balance

Other

Foods and beverages will be provided for participants for eight weeks. During the controlled feeding portion of the study the be based on evidence collected from What We Eat in America (WWEIA) data. Based on this data the participants will be provided a diet that reflects American dietary trends.

Primary outcomes

  1. Change in body weight

    Time frame: Measured weekly for weeks 1 through 10, and weeks 13, 17, 21, 24 and 28

    Body weight will be measured to the nearest 0.1 kg using a calibrated electronic scale.

Secondary outcomes

  1. Height

    Time frame: Week 1

    Height will be measured to the nearest 0.1 cm using a wall-mounted stadiometer.

  2. Change in body mass index

    Time frame: Measured weekly for weeks 1 through 10, and weeks 13, 17, 21, 24 and 28

    Body weight and height will be used to calculate Body Mass Index (BMI) as kg/m2.

  3. Change in body water (via InBody)

    Time frame: Week 1, 10, 28

    Measured using bioelectrical impedance analysis (BIA) with an InBody 770® expressed as kg.

  4. Change in body fat (via DEXA scan)

    Time frame: Week 1, 10, 28

    Fat mass (grams) will be measured using dual energy x-ray absorptiometry (DEXA).

  5. Change in waist circumference

    Time frame: Week 1, 10, 28

    Waist circumference is measured with an anthropometric tape. Measurements will be performed in duplicate and averages recorded to the nearest 0.1 cm.

  6. Change in hip circumference

    Time frame: Week 1, 10, 28

    Hip circumference is measured with an anthropometric tape. Measurements will be performed in duplicate and averages recorded to the nearest 0.1 cm.

  7. Change in waist to hip ratio

    Time frame: Week 1, 10, 28

    Waist and hip circumference will be expressed as a ratio.

  8. Change in resting systolic blood pressure

    Time frame: Week 1, 10, 28

    Blood pressure will obtained via automated instrument and blood pressure cuff. At least two measurements will be made, expressed in mmHg, and the average value will be recorded.

  9. Change in resting diastolic blood pressure

    Time frame: Week 1, 10, 28

    Blood pressure will obtained via automated instrument and blood pressure cuff. At least two measurements will be made, expressed in mmHg, and the average value will be recorded.

  10. Change in resting heart rate

    Time frame: Week 1, 10, 28

    Resting heart rate (pulse) will obtained via automated instrument in beats per minute.

  11. Genetic Risk of Obesity

    Time frame: Week 1

    Genomic DNA will be collected from white blood cells. A polygenic risk score (PRS) indexing genetic predisposition to obesity using known obesity single nucleotide polymorphisms (SNPs).

  12. Change in vascular health

    Time frame: Week 1, 5, 10

    Peripheral Arterial Tone (PAT) technology will be used to measure vascular health. The EndoPAT test is a non-invasive measurement of the overall health of the endothelium.

  13. Change in liver fat

    Time frame: Week 1 and 10

    Liver fat assessed from the Controlled Attenuation Parameter (CAP) computed from the liver stiffness measurement using the Fibroscan®

  14. Change in liver stiffness

    Time frame: Week 1 and 10

    Liver stiffness assessed from the shear wave speed with pulse echo ultrasound using the Fibroscan®

  15. Change in blood metabolite profiles

    Time frame: Week 1 and 10

    Analysis of metabolites, the small molecule substrates, intermediates and products of metabolism analyzed by mass spectrometry (MS). Includes branched chain amino acids, 2 hydroxybutyric acid, acylcarnitines, saturated, monounsaturated and polyunsaturated non-esterified fatty acids, triglyceride species, phospholipid species, bile acids and steroid hormones.

  16. Change in fasting blood glucose

    Time frame: Week 1, 10, 28

    This outcome will evaluate blood sugars levels in the fasted state.

  17. Change in hemoglobin A1C

    Time frame: Week 1, 10, 28

    This outcome will evaluate glycated hemoglobin as a reflection of the plasma glucose level during the past two to three months.

  18. Change in urinary sodium

    Time frame: Week 1, 5, 7 and 10

    Urinary sodium will be measured as indicators of dietary compliance during the feeding intervention of the study. All urine passed for a 24 hour period will be collected.

  19. Change in urinary potassium

    Time frame: Week 1, 5, 7 and 10

    Urinary potassium will be measured as indicators of dietary compliance during the feeding intervention of the study. All urine passed for a 24 hour period will be collected.

  20. Change in urinary nitrogen

    Time frame: Week 1, 5, 7 and 10

    Urinary nitrogen will be measured as indicators of dietary compliance during the feeding intervention of the study. All urine passed for a 24 hour period will be collected.

  21. Change in red blood cell fatty acids

    Time frame: Week 1, 10, 28

    Red blood cell fatty acids will be analyzed by mass spectrometry (MS).

  22. Change in C-reactive protein

    Time frame: Week 1, 10, 28

    C-Reactive Protein will be measured as a non-specific marker for inflammation.

  23. Change in carotenoid levels

    Time frame: Week 1 and 10

    Serum carotenoids, including vitamin A, alpha-carotene, and beta-carotene will be used to evaluate nutrient status and dietary intake of vegetables prior to feeding intervention and post feeding intervention.

  24. Change in total cholesterol

    Time frame: Week 1 and 10

    Total cholesterol will be collected to evaluate cardiac risk expressed as milligrams per deciliter (mg/dL).

  25. Change in high density lipoprotein (HDL) cholesterol

    Time frame: Week 1 and 10

    HDL cholesterol will be collected to evaluate cardiac risk expressed as milligrams per deciliter (mg/dL).

  26. Change in low density lipoprotein (LDL) cholesterol

    Time frame: Week 1 and 10

    LDL cholesterol will be collected to evaluate cardiac risk expressed as milligrams per deciliter (mg/dL).

  27. Change in triglycerides in response to a meal

    Time frame: Baseline and 1, 2, 3, and 6 hours after a challenge meal

    Triglycerides will be measured in blood (mg/dL).

  28. Change in ghrelin in response to a meal

    Time frame: Baseline and 1, 2, 3, and 6 hours after a challenge meal

    Ghrelin will be evaluated as an indicator of hunger signaling.

  29. Change in leptin in response to a meal

    Time frame: Baseline and 1, 2, 3, and 6 hours after a challenge meal

    Leptin will be evaluated as an indicator of satiety signaling.

  30. Change in insulin in response to a meal

    Time frame: Baseline and 1, 2, 3, and 6 hours after a challenge meal

    Insulin measured in blood using an antibody based assay. Will also be expressed as the quantitative insulin sensitivity check index (QUICKI).

  31. Change in Matsuda Index

    Time frame: Baseline and 1, 2 hours after a challenge meal

    Matsuda index will be calculated from plasma glucose and insulin.

  32. Change in resting metabolic rate

    Time frame: Week 1 and 10

    Respiratory gas exchange measurements (oxygen consumption-VO2 and carbon dioxide production-VCO2) will be made to determine metabolic rate using a metabolic cart system.

  33. Change in post-prandial metabolic rate

    Time frame: 1, 2, 3 and 6 hours after a meal

    Post-prandial metabolic rate measured using indirect calorimetry.

  34. Change in metabolic flexibility

    Time frame: Week 1 and 10

    The formula is designed to deliver approximately 800 kcals total with 60% kcals from fat (approximately 55 g of fat), 25% kcals from carbohydrates, and 15% of kcals from protein.

  35. Change in predicted VO2 max

    Time frame: Week 1, 10, 28

    Cardiorespiratory endurance will be evaluated by measuring heart rate (HR) and oxygen consumption (VO2) during a walking graded exercise test on a treadmill.

  36. Change in interstitial glucose levels

    Time frame: Week 1 and 10

    A continuous glucose monitor (CGM) will be used to continuously assess interstitial glucose levels. The Abbott Freestyle Libre Pro Sensor is inserted under the skin on the back of the arm. The sensor will measure the interstitial glucose level every fifteen minutes. Participants will wear the monitors for fourteen days.

  37. Change in executive function

    Time frame: Week 1 and 10

    Assessed using Cambridge Gambling Task (CGT), from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  38. Change in response speed

    Time frame: Week 1 and 10

    Assessed using Motor Screening Task (MOT), from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  39. Change in verbal memory

    Time frame: Week 1 and 10

    Assessed using Verbal Recognition Memory (VRM) task from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  40. Change in psycho-motor speed

    Time frame: Week 1 and 10

    Assessed using Reaction Time (RTI) task from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  41. Change in spatial memory

    Time frame: Week 1 and 10

    Assessed using Spatial Working Memory (SWM) task from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  42. Change in multitasking

    Time frame: Week 1 and 10

    Assessed using Multitasking Test (MTT) from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  43. Change in social cognition

    Time frame: Week 1 and 10

    Assessed using Emotional Recognition (ERT) task from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  44. Change in attentive function

    Time frame: Week 1 and 10

    Assessed using Stop Signal Task (STT) from Cambridge Neuropsychological Test Automated Battery (CANTAB).

  45. Change in allostatic load

    Time frame: Week 1, 10, 28

    Allostatic load (AL) is an aggregate value derived from several parameters that assess physiologic adaptive response to neural or neuroendocrine stressors. The following measures are used to determine the AL score: Urinary cortisol and catecholamine levels, resting blood pressure, waist to hip ratio, blood levels of high sensitivity C-Reactive Protein, cholesterol, dehydroepiandrosterone sulfate and hemoglobin A1c, and urinary levels of epinephrine and norepinephrine.

  46. Change in continuous systolic blood pressure

    Time frame: Week 1 and 10

    Blood pressure measured using a Continuous Non-invasive Arterial Pressure (CNAP®) device in mmHg.

  47. Change in continuous diastolic blood pressure

    Time frame: Week 1 and 10

    Blood pressure measured using a Continuous Non-invasive Arterial Pressure (CNAP®) device in mmHg.

  48. Change in mean arterial blood pressure

    Time frame: Week 1 and 10

    Blood pressure measured using a Continuous Non-invasive Arterial Pressure (CNAP®) device in mmHg .

  49. Change in mood

    Time frame: Week 1 and 10

    Mood assessed using the Profile of Mood States (POMS). Total Mood Disturbance (TMD) score is found from the difference between "negative" subscales - "positive" subscales. Individual scores on the POMS range from -32 to 200 with higher scores indicating higher mood disturbance.

  50. Change in perceived stress

    Time frame: Week 1, 6, 10, 19 and 28

    Perceived stress measured using the Perceived stress scale (PSS). Scores on the PSS can range from 0 to 40 with higher scores indicating higher perceived stress. Responses for individual questions are summed to a total score.

  51. Change in self-efficacy

    Time frame: Week 10, 19 and 28

    This 20 item questionnaire is a measurement of the capacity to execute behaviors necessary to change their weight and begin to implement exercise in their lives regularly.

  52. Change in diet satisfaction

    Time frame: Week 1, 19 and 28

    This 28 item questionnaire acts as a valid instrument for assessing diet satisfaction in the context of weight-management. This measurement assesses diet satisfaction both within and outside the context of weight-loss treatment, as well as to assesses change in satisfaction as a result of treatment.

  53. Change in appetite

    Time frame: Week 1 and 10

    A computer tablet with stylus will be used to assess hunger and appetite, defined as perceived hunger, fullness, desire to eat, prospective consumption and other measures of food craving and perceived hypoglycemia. Questions will be presented one-by-one on the screen and participants will be asked to express their response using visual analog scales (VAS). This measurement will be evaluated during the meal challenge assessment.

  54. Three factor eating questionnaire

    Time frame: Week 1 and 10

    This 18 item questionnaire is used to examine three dimensions of human eating behavior including cognitive restraint, disinhibition or uncontrolled eating and hunger.

  55. Barriers to physical activity

    Time frame: Week 1

    Participants will be asked to complete the Barriers to Being Active questionnaire.

  56. Usual physical activity

    Time frame: Week 1

    An accelerometer (Actical) will be continuously worn by participants during waking hours (excluding bathing and swimming) for a period of 7 days.The measure of usual physical activity is used to estimate total energy expenditure and energy requirements.

  57. Diet acceptability

    Time frame: Week 10

    This measurement is an evaluation of palatability, ease of preparation, satisfaction, and perceived benefits and adverse effects related to a prescribed controlled feeding diet.

  58. Yale Food Addiction Scale

    Time frame: Week 1

    Measures markers of substance dependence with the consumption of high fat/high sugar foods. This is a 25-item self-report measure that includes mixed response categories (dichotomous and Likert-type format).

  59. Changes in dietary intake

    Time frame: Week 1, 19, and 28

    Three non-consecutive twenty-four hour dietary recalls will be collected when subjects are self-selecting their 'usual' diets. A three day average nutrient intake will be expressed.

  60. Change in stress reactivity

    Time frame: Week 1 and 10

    Acute stress reactivity will be assessed by measuring salivary cortisol concentrations in response to a challenging task.

  61. Change in heart rate variability

    Time frame: Week 1 and 10

    Autonomic physiological functioning will be assessed using the MindWare Cardio/Galvanic Skin Response (GSR) system, a device that connects to the subject's torso with eight disposable electrodes and a heart rate monitor. Emotional arousal via skin conductance, a form of electrodermal activity (EDA) is also measured.

  62. Change in Food Choice

    Time frame: Week 1 and 10

    Food choice computer-based tests from Leeds, United Kingdom, will be used to estimate explicit liking and implicit wanting for several different categories of foods.

  63. Change in oxygen consumption rate (OCR)

    Time frame: Week 1 and 10

    Measured in peripheral blood mononuclear cells by use of Seahorse XF Analyzer, a tool for measuring glycolysis and oxidative phosphorylation (through oxygen consumption) simultaneously in the same cells.

  64. Change in extracellular acidification rate (ECAR)

    Time frame: Week 1 and 10

    Measured in peripheral blood mononuclear cells by use of Seahorse XF Analyzer, a tool for measuring glycolysis and oxidative phosphorylation (through oxygen consumption) simultaneously in the same cells.

  65. Change in fecal microbiome

    Time frame: Week 1, 10 an 28

    Assays will be performed on fecal samples to determine DNA representing the colonic microbiota.

Study contacts

Contact information is provided by the study sponsor or research team.

Beverly Miller, BS, RDN

CONTACT

[email protected]

530-754-2541

Ellen Bonnel, PhD

CONTACT

[email protected]

530-752-4184

Sponsors and collaborators

Lead sponsor

USDA, Western Human Nutrition Research Center

Fed

Registry information

Acronym: DGA4ME

Important dates

Study start
2022
Primary completion
2026
Study completion
2026
First posted
Mar 3, 2020
Registry last updated
Apr 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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