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Protocol Details

Effect of Ultra Processed versus Unprocessed Diets on Energy Intake

This study is NOT currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

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

Recruitment Detail

Type: Completed Study; data analyses ongoing
Gender: Male & Female
Min Age: 18 Years
Max Age: 50 Years

Referral Letter Required


Population Exclusion(s)

Pregnant Women;
Adults who are or may become unable to consent;
Non-English Speaking;


Food Intake;
Body Composition;
Body Weight Regulation

Recruitment Keyword(s)



Healthy Diet

Investigational Drug(s)


Investigational Device(s)



Dietary Supplement: Ultra-processed diet
Dietary Supplement: Unprocessed diet

Supporting Site

National Institute of Diabetes and Digestive and Kidney Diseases


Eating too much processed food is believed to lead to obesity. But the effect of processed food on energy intake has not been carefully studied. Researchers want to study people s diets for 4 weeks and do specialized tests of the effects. Participants will get two diets. They will have the same calories and nutrients, but one diet will be unprocessed food and the other will be ultra-processed.


To better understand how processed and unprocessed foods affect daily food consumption and how the body handles blood sugar.


Healthy adults ages 18-50 who have stable weight and can exercise


Participants will not eat for 12 hours. Then they will be screened with:

-Medical history

-Physical exam

-Heart and blood tests

-Resting energy expenditure test (REE). A hood will collect air exhaled while lying down for 30-40 minutes.

-Psychiatric questions

-Questions about mood, eating, sleep, and socioeconomic status

-20-minute stationary biking

Female participants will have a urine pregnancy test.

Participants will stay in the clinic for 4 weeks. For 2 weeks they will get a processed diet. For the other 2 weeks they will get an unprocessed diet. Participants cannot use the study period to gain or lose weight.

Participants will have:

-Meals and snacks provided

-Daily exercise

-Blood, urine, and saliva tests

-To drink a special water and a very sweet liquid


-Scans and X-rays

-To wear activity monitors and a device to measure blood sugar

-Several 24-hour periods in a room that measures oxygen and carbon dioxide

-Repeats of screening questions

-Questions about hunger and meals

-Sleep monitoring

-Taste tests

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1. Adults age 18-50 years, male and female

2. Weight stable (< +/- 5 % over past 6 months)

4. Body mass index (BMI) greater than or equal to 18 kg/m^2

5. Willing to cease their habitual caffeine intake during the study, beginning one week prior to inpatient admission

6. Written informed consent

7. Willing to eat the food provided in the study

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


1. Evidence of metabolic or cardiovascular disease, or disease that may influence metabolism (e.g. cancer, diabetes, thyroid disease)

2. Taking any prescription medication or other drug that may influence metabolism (e.g. diet/weight-loss medication, asthma medication, blood pressure medication, psychiatric medications, corticosteroids, or other medications at the discretion of the PI and/or study team)

3. Hematocrit < 34% (women only)

4. Hematocrit < 40% (men only)

5. Pregnancy, lactation (women only)

6. Participating in a regular exercise program (> 2h/week of vigorous activity)

7. Caffeine consumption > 300 mg/day

8. Regular use of alcohol (> 2 drinks per day), tobacco (smoking or chewing) amphetamines, cocaine, heroin, or marijuana over past 6 months

9. Eating disorders or psychological conditions, such as (but not limited to) claustrophobia, clinical depression, bi-polar disorders, that would be incompatible with safe and successful participation in this study, as determined by investigators.

--Past or present history of claustrophobia since part of the protocol will involve being confined to a small room for whole-body indirect calorimetry and being in an MRI scanner for liver fat measures

10. Implants, devices, or foreign objects implanted in the body that interfere with the Magnetic Resonance procedures

11. Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, food allergies)

12. Volunteers unwilling or unable to give informed consent

13. Non-English speakers due to unavailability of required questionnaires in other languages.

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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

Michael S. Stagliano, C.R.N.P.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
(301) 827-3198

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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