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Healthy VolunteersNCT02939404

Food Intake Response to Short-Term Modifications of Metabolism in Humans

A study testing Cold exposure, Normal temperature and Fixed diet in people with Healthy Volunteers, run by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

One reason people gain weight is eating more calories from food than what they need for energy over 24 hours. Metabolism is the amount of energy a person uses over 24 hours. Researchers want to study the relationship between changes in metabolism and how much a person eats. Read more about this study

Who is it for?
Ages 18 to 55 years
Conditions the study is for
Healthy Volunteers
What is being tested?
Cold exposure, Normal temperature and Fixed diet
Could I receive a placebo?
No, everyone receives an active treatment
How many people
54 participants
Where
1 siteUnited States
Study dates
27 Apr 2017to 24 Jun 2024
Phase
Interventional
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 55 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • Premenopausal women and men <55 years of age
  • Body weight <204 kg (<450 pounds) and >= 36 kg (>= 80 pounds)
  • Stable weight (+/-5% within past 6 months) as determined by volunteer report
  • Healthy, as determined by medical history, physical examination, and laboratory tests

Who cannot join

  • Age <18 years
  • Weight greater than or equal to 204 kg (greater than or equal to 450 pounds, maximum weight of the iDXA machine as per manufacturer s manual), or weight <36 kg (<80 pounds, minimum weight allowed based on the NIH guidelines of blood drawing for research purposes)
  • Use of medications affecting metabolism and appetite in the last three months
  • Expresses unwillingness to consume all food given during the weight maintaining diet portions of the study (e.g., due to strict dietary restrictions including allergies or vegetarian or kosher diet)
  • Current use of tobacco products, marijuana, amphetamines, cocaine, or intravenous drug use
  • Current pregnancy, pregnancy within the past 6 months or lactation
Show all 21Show fewer
  • History or clinical manifestation of:
  • Type 1 and Type 2 diabetes mellitus
  • History of surgery for the treatment of obesity
  • Endocrine disorders, such as Cushing s disease, pituitary disorders, and hypo and hyperthyroidism
  • Pulmonary disorders, including chronic obstructive pulmonary disease
  • Cardiovascular diseases, including coronary heart disease, heart failure, arrhythmias, and peripheral artery disease
  • High blood pressure by sitting blood pressure measurement using an appropriate cuff higher than 140/90 mmHg on two or more occasions, or current antihypertensive therapy
  • Liver disease, including cirrhosis, active hepatitis B or C, and AST or ALT greater than or equal to 2x normal
  • Gastrointestinal disease including Crohn s disease, ulcerative colitis, celiac disease or other malabsorptive disorders
  • Abnormal kidney function (eGFR <60 mL/min/1.73m(2))
  • Central nervous system disease, including previous history of cerebrovascular accidents, dementia, neurodegenerative disorders or history of severe head trauma
  • Cancer requiring treatment in the past five years, except for nonmelanoma skin cancers or cancers that have clearly been cured
  • Infectious disease such as active tuberculosis, HIV (by self report), chronic coccidiomycoses or other chronic infections that might influence EE and weight
  • Diagnosis of binge eating disorder, anorexia and major psychiatric disorders based upon the DSM-IV including depression, schizophrenia and psychosis, which may impact the ability of the participant to be in the respiratory chamber for 24 hour time periods
  • Chronic ethanol use (more than 3 drinks/day)

Trial locations and contacts

1 site in 1 country.

United States1 site

  • NIDDK, Phoenix

    Phoenix, Arizona, 85014

Other trials in United States

About this study

Official title: Energy Intake Response to Short-Term Alterations of Energy Expenditure in Humans

One reason people gain weight is eating more calories from food than what they need for energy over 24 hours. Metabolism is the amount of energy a person uses over 24 hours. Researchers want to study the relationship between changes in metabolism and how much a person eats.

Objectives:

Read more

To see how much food a person eats when the body's temperature is cooled. To study how changes in metabolism may alter the amount of food a person eats.

Eligibility:

Healthy people ages 18-55.

Design:

Participants will stay at NIH for 20 days.

During the first 4 days, participants will have:

  • Medical exam
  • Electrocardiogram
  • Blood and urine tests. One blood test includes drinking a sugar solution.
  • DXA body composition scan
  • Questions about foods they like, physical activity, and personal behavior
  • Exercise test on a stationary bicycle

Participants will spend 24-hour periods in a metabolic chamber. The chamber will be at normal room temperature or cooler.

Some times, participants will eat a diet that matches their daily needs (fixed or eucaloric). Other times, they can eat as much as they wish from a vending machine (ad libitum).

Participants will have blood and urine collected.

Participants will swallow an ingestible wireless sensor and wear a small data recorder device.

On the second to last day, participants will stay in the metabolic chamber but only consume water and non-caffeinated sugar-free beverages.

Participants will come back for 1-day visits at six months and one year from the first admission. They will have blood and urine tests, and a DXA scan. They will answer questions on physical activity and food habits.

Read the detailed description

More than 30% of adults are considered overweight. In general, lifestyle changes (diet and exercise) or current weight loss drugs only lead to about 5 to 10% weight loss. This may be because a person's energy expenditure, aka the number of calories the body uses, leads to hunger and may increase the amount of food a person eats. Cold exposure is known to increase metabolism but it may not lead to weight loss if appetite and the desire for food are also increased. The primary goal of this study is to evaluate whether changing energy expenditure by cool temperature exposure results in changes in food intake. This study will involve a stay on our clinical research unit where we will determine the energy requirements (at 24 degree C) of 68 healthy, adult volunteers without evidence of diabetes. Exposure to cool temperatures (19 degree C) will be used to increase the number of calories a person's body uses in a day. Participants will spend 24 hours in a room that measures energy expenditure while the temperature in the room is turned down, once with a fixed diet (eucaloric) and once with a buffet of food choices (ad libitum). After the fixed diet, volunteers will self-select how much food they wish to eat for one day from a vending machine. Volunteers will also spend one day fasting followed by a day self-selecting their food from the vending machine. Findings from this study will provide knowledge about a possible causal link between energy expenditure and eating behavior. This information may shed light on why many weight loss interventions that increase energy expenditure do not work as well as expected, and may eventually lead to new weight loss approaches and therapies.

Being tested
Cold exposure, Normal temperature, Fixed diet, Ad libitum diet, Fasting
Keywords
Energy Intake, Energy Expenditure, Eating Behavior, Cold Exposure, Natural History
Medical subject headings
Feeding Behavior

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Cold exposureOther

    23.25 hours inside respiratory chamber with the temperature set to19°C

  • Normal temperatureOther

    23.25 hours inside respiratory chamber with the temperature set to 24°C

  • Fixed dietOther

    Also called Eucaloric diet

    A diet that matches the participant's caloric needs

  • Ad libitum dietOther

    Participants can eat as much as they want

  • FastingOther

    Participants do not eat for 12 hours before and 24 hours in chamber

Study groups in NCT02939404
Study groupRoleWhat they receive
1. Chamber at 24C, fixed dietExperimentalChamber at room temperature (24C) with a fixed eucaloric diet
Receives: Other: Normal temperature; Other: Fixed diet
2. Chamber at 24C, ad libitum dietExperimentalChamber at room temperature (24C) with an ad libitum diet (self-select how much food they wish to eat)
Receives: Other: Normal temperature; Other: Ad libitum diet
3. Chamber at 19C, fixed dietExperimentalChamber at cold temperature (16C) with a fixed eucaloric diet
Receives: Other: Cold exposure; Other: Fixed diet
4. Chamber at 19C, ad libitum dietExperimentalChamber at cold temperature (19C) with an ad libitum diet (self-select how much food they wish to eat)
Receives: Other: Cold exposure; Other: Ad libitum diet
5. Chamber at 24C, fastingExperimentalChamber at room temperature (24C) fasting while in chamber and 12 hours before
Receives: Other: Normal temperature; Other: Fasting

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. 24-hour Energy Expenditure (kcal)

    Energy expenditure (EE) as measured during 24 hours in a whole-room calorimeter

    Measured: Days 6 (Chamber at 24°C, fixed diet), 10(Chamber at 24°C, ad libitum diet), 14(Chamber at 19°C, fixed or ad libitum diet), 18(Chamber at 19°C, fixed or ad libitum diet), and 21(Chamber at 24°C, fasting)

  2. 24-hour Energy Intake (kcal)

    Energy intake as measured during 24 hours in a whole-room calorimeter

    Measured: Days 6 (Chamber at 24°C, fixed diet), 10(Chamber at 24°C, ad libitum diet), 14(Chamber at 19°C, fixed or ad libitum diet), 18(Chamber at 19°C, fixed or ad libitum diet), and 21(Chamber at 24°C, fasting)

Secondary outcomes (8)

  1. 24- Hour Respiratory Quotient (RQ)

    RQ, an approximation for the ratio of carbohydrate-to-fat oxidation rates, is measured while in the chamber

    Measured: Days 6 (Chamber at 24°C, fixed diet), 10(Chamber at 24°C, ad libitum diet), 14(Chamber at 19°C, fixed or ad libitum diet), 18(Chamber at 19°C, fixed or ad libitum diet), and 21(Chamber at 24°C, fasting)

  2. Leptin

    Plasma leptin (ng/ml)

    Measured: Days 6 (Chamber at 24°C, fixed diet), 14(Chamber at 19°C, fixed diet) or 18(Chamber at 19°C, fixed diet), and 21(Chamber at 24°C, fasting)

  3. Secretin

    Plasma secretin (ng/ml)

    Measured: Days 6 (Chamber at 24°C, fixed diet), 14(Chamber at 19°C, fixed diet) or 18(Chamber at 19°C, fixed diet), and 21(Chamber at 24°C, fasting)

  4. Ghrelin

    Plasma grehlin (pg/ml)

    Measured: Days 6 (Chamber at 24°C, fixed diet), 14(Chamber at 19°C, fixed diet) or 18(Chamber at 19°C, fixed diet), and 21(Chamber at 24°C, fasting)

  5. FGF-21

    Plasma FGF-21 (pg/ml)

    Measured: Days 6 (Chamber at 24°C, fixed diet), 14(Chamber at 19°C, fixed diet) or 18(Chamber at 19°C, fixed diet), and 21(Chamber at 24°C, fasting)

  6. Core Body Temperature (C)

    Core body temperature measured in chamber

    Measured: Days 6 (Chamber at 24°C, fixed diet), 14(Chamber at 19°C, fixed diet) or 18(Chamber at 19°C, fixed diet), and 21(Chamber at 24°C, fasting)

  7. Weight Change at 6 Months

    Weight change from baseline to 6 months

    Measured: 6 months

  8. Weight Change at 12 Months

    Weight change from baseline to 12 months

    Measured: 12 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted20 Oct 2016 (estimated)
  2. Study start27 Apr 2017
  3. Primary completion24 Jun 2024
  4. Study completion24 Jun 2024

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
None (open label)
Enrolment
54 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT02939404
Sponsor's protocol ID
999917004
Other IDs
17-DK-N004
Status last verified
3 Jul 2024
First submitted
19 Oct 2016
Last updated
4 Jul 2025
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Publications

  • Fry HT, Gluck ME, de Baca TC, Stinson EJ, Unlu Y, Piaggi P, Krakoff J, Chang DC. Hunger on the Three-Factor Eating Questionnaire Is Associated With Increased Ad Libitum Energy Intake in Different Conditions. Obesity (Silver Spring). 2026 Apr;34(4):801-810. doi: 10.1002/oby.70148. Epub 2026 Feb 18.

    PubMed 41709501

  • Unlu Y, Piaggi P, Stinson EJ, De Baca TC, Rodzevik TL, Walter M, Fry H, Krakoff J, Chang DC. Cold induces increased ad libitum energy intake independent of changes in energy expenditure: a controlled crossover trial in adults. Am J Clin Nutr. 2025 Feb;121(2):293-303. doi: 10.1016/j.ajcnut.2024.12.013. Epub 2024 Dec 14.

    PubMed 39675563

  • Hollstein T, Heinitz S, Ando T, Rodzevik TL, Basolo A, Walter M, Chang DC, Krakoff J, Piaggi P. Metabolic Responses to 24-Hour Fasting and Mild Cold Exposure in Overweight Individuals Are Correlated and Accompanied by Changes in FGF21 Concentration. Diabetes. 2020 Jul;69(7):1382-1388. doi: 10.2337/db20-0153. Epub 2020 Apr 27.

    PubMed 32341039

  • Hollstein T, Basolo A, Ando T, Votruba SB, Walter M, Krakoff J, Piaggi P. Recharacterizing the Metabolic State of Energy Balance in Thrifty and Spendthrift Phenotypes. J Clin Endocrinol Metab. 2020 May 1;105(5):1375-92. doi: 10.1210/clinem/dgaa098.

    PubMed 32118268

Questions about this trial

What is this clinical trial studying?

A study testing Cold exposure, Normal temperature and Fixed diet in people with Healthy Volunteers, run by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 4 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 4 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

24-hour Energy Expenditure (kcal) (time frame: Days 6 (Chamber at 24°C, fixed diet), 10(Chamber at 24°C, ad libitum diet), 14(Chamber at 19°C, fixed or ad libitum diet), 18(Chamber at 19°C, fixed or ad libitum diet), and 21(Chamber at 24°C, fasting)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT02939404, which also lists 4 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Jul 2025.

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