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Protocol Details

Effect of Ultra-processed versus Unprocessed Diets on Energy Metabolism

This study is currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Recruitment Detail

Type: Participants currently recruited/enrolled
Gender: Male & Female
Min Age: 18 Years
Max Age: 60 Years

Referral Letter Required


Population Exclusion(s)

Pregnant Women;
Adults who are or may become unable to consent;


Body Weight;
Food Intake;
Body Mass Index

Recruitment Keyword(s)



Healthy Diet;

Investigational Drug(s)


Investigational Device(s)



Other: Ultra-processed food, high energy density
Other: Ultra-processed food, both low
Other: Ultra-processed food, both high
Other: Unprocessed food diet

Supporting Site

National Institute of Diabetes and Digestive and Kidney Diseases

Protocol Number: 22DK0002

Title: Effects of Ultra-processed versus Unprocessed Diets on Energy Metabolism


Many diets worldwide include both processed and unprocessed foods. Researchers want to study the effects these foods have on a person s health.


To study how different diets affect a person s health and metabolism.


Adults aged 18 60 without diabetes who have stable weight and can exercise.


Participants will be screened with:

Medical history

Physical exam

Heart tests

Resting energy expenditure (to determine calorie needs)

Blood and urine tests

20-minute stationary bicycle session

Food, diet, and mental health questionnaires

Participants will stay at NIH for 4 weeks. They will receive 3 meals a day and may eat as little or as much as they want. The diet will change each week. Their weight will be recorded daily. They will ride a stationary bicycle daily. Each week, they will do the following:

Spend 1 day in a special room that assesses their metabolism

Have 24-hour urine collections

Give skin and fecal samples

Repeat some screening tests

Have scans to measure body fat

Complete computerized behavior tasks

Wear an activity monitor to track physical activity

Wear a glucose monitor. A sensor will be inserted under the skin with a small needle. It will be replaced weekly.

Take taste tests. They will swish water and flavored liquids around in their mouth and pick which ones had a non-neutral taste. They will also compare liquids for which ones taste better.

Participation will last for 4 weeks.

Sponsoring Institution: National Institute of Diabetes and Digestive and Kidney Diseases

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In order to be eligible to participate in this study, an individual must meet all of the following criteria:

- Provision of signed and dated informed consent form

- Adults age 18-60 years, male and female

- Weight stable (< +/- 5 % body weight change over past 6 months) as determined by volunteer report

- Body mass index (BMI) > =20 kg/m2

- Body weight > = 53 kg

- Able to complete daily bouts of stationary cycling at a moderate rate and intensity with a HR equal to or greater than 0.3(SqrRoot) (220-age-HRrest)+HRrest but not exceeding 0.4(SqrRoot) (220-age-HRrest)+HRrest and no signs of arrhythmia

- Willingness to comply with all study procedures and Lifestyle Considerations for the duration of the study per the discretion of the PI.


An individual who meets any of the following criteria will be excluded from participation in this study:

-Evidence of diseases or conditions that may influence appetite (e.g., cancer, diabetes, alterations of smell or taste post COVID-19), or other conditions at the discretion of the PI and/or study team).

-Taking prescription medications or other drugs that may influence appetite (including, but not limited to, diet/weight-loss medication or other medications at the discretion of the PI and/or study team)

-Positive pregnancy test or lactation as determined by volunteer report (women only)

-Participating in a regular exercise program (> 2h/week of vigorous activity) as determined by volunteer report

-Hematocrit < 37% (women only)

-Hematocrit < 40% (men only)

-Caffeine consumption > 300 mg/day as determined by volunteer report

- Alcohol consumption > 3 drinks per day for men or > 2 drinks per day for women as determined by volunteer report

-Regular use of tobacco (smoking or chewing), amphetamines, cocaine, heroin, or marijuana over past 6 months as determined by volunteer report. Subjects may also be excluded based on a urine drug test.

-Psychological conditions as determined by volunteer report such as (but not limited to) eating disorders, depression, bipolar disorders, that would be incompatible with safe and successful participation in this study, as determined by investigators

-Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, food allergies) or a reported dislike of a significant fraction of the study foods

-Volunteers unwilling or unable to give informed consent

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Not Provided

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Principal Investigator

Referral Contact

For more information:

Kevin Hall, Ph.D.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
National Institutes of Health
Building 12A
Room 4007
12 South Drive
Bethesda, Maryland 20892
(301) 402-8248

Nan Zhai, C.R.N.P.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
(301) 827-3324

Office of Patient Recruitment
National Institutes of Health Clinical Center (CC)
Building 61, 10 Cloister Court
Bethesda, Maryland 20892
Toll Free: 1-800-411-1222
Local Phone: 301-451-4383
TTY: TTY Users Dial 7-1-1

Clinical Trials Number:


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