ObesityNCT01967563
Study of the Effect of a Very-Low-Carbohydrate Diet on Energy Expenditure
An observational study of Obesity and Appetite, run by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) at 1 site in United States.
Trial summary
Background: Popular weight loss plans often restrict carbohydrates or fat. Research shows that very-low-carbohydrate (ketogenic) diets lead to greater weight loss than low-fat diets. Researchers want to know if eating fewer carbohydrates changes the number of calories the body uses. Read more about this study
- Who is it for?
- Ages 18 to 50 years, men only
- Conditions the study is for
- Obesity, Appetite, Healthy Volunteers
- How many people
- 5 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Dec 2013to 23 Feb 2015
- Phase
- Observational
- Are there results?
- None posted in the registry
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 50 years
- Men only
- No healthy volunteers
- Adult
Study population: We will study the magnitude and variability of energy expenditure changes in response to a eucaloric ketogenic diet subsequent to a standard energy- and macronutrient-balanced diet in overweight and class I obese adult male volunteers
Who may be able to join
- Age 18-50 years, male
- Weight stable (< 5 % over past 6 months)
- Current stable weight no more than 8% below lifetime maximum weight
- Body mass index (BMI) greater than or equal to 25 kg/m(2) but less than 35 kg/m(2), with each study site recruiting an equal number of subjects from the overweight range of 25 kg/m(2) less than or equal to BMI < 30 kg/m(2) and from the class I obese range of 30 kg/m(2) less than or equal to BMI < 35 kg/m(2)
- Otherwise healthy, as determined by medical history and laboratory tests
- Able to complete daily bouts of stationary cycling at a moderate rate and intensity
Show all 9Show fewer
- Written informed consent
- Willing to eat all the food provided in the study
- Willing to continue consistently their habitual caffeine intake
Who cannot join
- BMI < 25 kg/m(2) or greater than or equal to 35 kg/m(2)
- Blood pressure > 140/90 mm Hg
- Evidence of metabolic or cardiovascular disease, or disease that may influence metabolism (e.g. cancer, diabetes, thyroid disease)
- 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)
- Hematocrit < 40%
- Participating in a regular exercise program (> 2h/week of vigorous activity)
Show all 12Show fewer
- Dietary carbohydrate less than 30% or greater than 65% of total calories as determined by food frequency questionnaire
- Caffeine consumption > 300 mg/day
- Regular use of alcohol (> 2 drinks per day), tobacco (smoking or chewing) amphetamines, cocaine, heroin, or marijuana over past 6 months
- Past or present history of eating disorder (including binge eating) or psychiatric disease, including claustrophobia since part of the protocol will involve being confined to a small room for whole-body indirect calorimetry
- Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, multiple food allergies)
- Volunteers unwilling or unable to give informed consent
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institutes of Health Clinical Center
Bethesda, Maryland, 20892
About this study
Official title: Effect of a Eucaloric Ketogenic Diet on Energy Expenditure: A Pilot Study
Background:
- Popular weight loss plans often restrict carbohydrates or fat. Research shows that very-low-carbohydrate (ketogenic) diets lead to greater weight loss than low-fat diets. Researchers want to know if eating fewer carbohydrates changes the number of calories the body uses. They also want to know how a ketogenic diet affects hunger, hormones, and food preferences.
Read more
Objectives:
- To better understand how the body responds to different diets.
Eligibility:
- Men 18 to 50 years old who are healthy but overweight.
Design:
- Participants will have 3 screening visits:
- Medical history, physical exam, blood test, and EKG. They will eat during the visit.
- For the week before the visit, participants will wear physical activity monitors daily. They will record everything they eat and sample the special diet. At the visit, they will receive an EKG and heart rate test while biking for 30 minutes.
- For the week before the visit, participants will wear the physical activity monitors. They will eat all their meals from the special diet that will be provided. At the visit, they will answer questions and bike for 60 minutes.
- After screening, for 1 week, participants will visit the clinic daily to receive that day s food. They will not eat or drink anything else except water.
- Then participants will stay at the clinic for 8 weeks. They cannot leave but can have visitors. Participants will wear physical activity monitors, bike daily, and follow different diets. Tests will be given daily, and may include weighing, X-rays, and blood and urine tests. They will spend several days in a monitored room to test oxygen and carbon dioxide.
Read the detailed description
Popular weight loss strategies often prescribe targeted reduction of dietary carbohydrate or fat. Recent clinical trials in obese subjects have found that low-carbohydrate diets result in greater weight loss compared with low-fat diets on a time scale of months when diet adherence was likely the highest. One hypothesis regarding the mechanism of improved weight loss with low carbohydrate diets is that such diets significantly modify the body s hormonal milieu to influence metabolic regulation and energy expenditure. Low-carbohydrate diets may thereby offer a metabolic advantage over low fat diets. In addition, low-carbohydrate diets may also decrease hunger or increase satiety compared to low-fat diets.
Determining the mechanism whereby one diet leads to greater weight loss than another is hampered by the inability to accurately measure food intake or physical activity in an outpatient setting. Thus, an inpatient feeding study lasting many weeks is required to accurately measure energy balance differences between isocaloric diets that differ in macronutrient composition. In this pilot multicenter cross-over study in 16 overweight and class I obese men, we will measure changes in energy expenditure in response to 4 weeks of inpatient feeding of a eucaloric, very low carbohydrate, ketogenic diet (5% Carbohydrate, 15% Protein, 80% Fat) immediately following an inpatient period of at least 4 weeks of consuming an energy balanced standard American diet (50% Carbohydrate, 15 % Protein, 35% Fat).
- Conditions
- Obesity, Appetite, Healthy Volunteers
- Keywords
- Energy Expenditure, Obesity, Carbohydrate, Fat, Ketones, Natural History
- Medical subject headings
- Obesity, Platelet Glycoprotein IV Deficiency, Ketosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| overweight and class I obese adult male volunteers | Adult Male Subjects will be recruited to determine the effects on energy expenditure of transitioning from an energy-and macronutrient-balanced standard baseline diet to a eucaloric ketogenic diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
To determine 24hr energy expenditure, respiratory quotient, and sleeping energy expenditure following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet.
the subjects will spend the 4th, 5th, 11th, 12th, 18th, 19th, 25th and 26th days of Stages 2 \& 3 in the metabolic chamber to measure 24-hour energy expenditure and sleeping energy expenditure. The energy expenditure calculations will be corrected for urinary ketone excretion since approximately 0.33 L of O2 is consumed for every gram of ketone excreted in the urine.
Measured: 1 year
Secondary outcomes (2)
To investigate changes in body composition and appetitive behaviors such as hunger, satiety, food impulsivity, and food liking & wanting during a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced stan...
hunger and satiety assessments will be completed multiple times each day, and ad libitum meal tests and appetitive computer tasks (delay discounting, liking \& wanting, go/no-go, food choice) will be performed during the latter periods of Stages 2 \& 3.
Measured: 7 days(outpatient) plus 8 weeks( inpatient)
To determine body weight and body composition following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet.
measurement of body composition by DXA, isotope dilution, and air-displacement plethysmography (BodPod) will be performed on the 15th and 28th days of Stages 2 \& 3. Measurement of total body water by administering deuterium oxide will be performed on the 28th day of Stages 2 \& 3. Body weight will be measured daily.
Measured: 7 days (outpatient) plus 8 weeks (inpatient)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Oct 2013 (estimated)
- Study start3 Dec 2013
- Primary completion23 Feb 2015
- Study completion23 Feb 2015
Why it stopped: PI is no longer at NIH
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 5 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Collaborators
- Pennington Biological Research Center, Translational Research Institute for Metabolism and Diabetes, Columbia University
- Responsible party
- Sponsor
- Investigators
- Kevin Hall, Ph.D., Principal investigator, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01967563
- Sponsor's protocol ID
- 130212
- Other IDs
- 13-DK-0212
- Status last verified
- Apr 2025
- First submitted
- 22 Oct 2013
- Last updated
- 22 Apr 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Rosenbaum M, Hall KD, Guo J, Ravussin E, Mayer LS, Reitman ML, Smith SR, Walsh BT, Leibel RL. Glucose and Lipid Homeostasis and Inflammation in Humans Following an Isocaloric Ketogenic Diet. Obesity (Silver Spring). 2019 Jun;27(6):971-981. doi: 10.1002/oby.22468. Epub 2019 May 8.
PubMed 31067015Hall KD, Guo J, Chen KY, Leibel RL, Reitman ML, Rosenbaum M, Smith SR, Ravussin E. Methodologic considerations for measuring energy expenditure differences between diets varying in carbohydrate using the doubly labeled water method. Am J Clin Nutr. 2019 May 1;109(5):1328-1334. doi: 10.1093/ajcn/nqy390.
PubMed 31028699Koppel N, Bisanz JE, Pandelia ME, Turnbaugh PJ, Balskus EP. Discovery and characterization of a prevalent human gut bacterial enzyme sufficient for the inactivation of a family of plant toxins. Elife. 2018 May 15;7:e33953. doi: 10.7554/eLife.33953.
PubMed 29761785Hall KD, Chen KY, Guo J, Lam YY, Leibel RL, Mayer LE, Reitman ML, Rosenbaum M, Smith SR, Walsh BT, Ravussin E. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016 Aug;104(2):324-33. doi: 10.3945/ajcn.116.133561. Epub 2016 Jul 6.
PubMed 27385608
Study at a glance
From the registry record, last updated by the sponsor on 22 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of a Eucaloric Ketogenic Diet on Energy Expenditure: A Pilot Study
- ClinicalTrials.gov ID
- NCT01967563
- Acronym / sponsor ID
- 130212
- Conditions
- Obesity, Appetite, Healthy Volunteers
- Keywords
- Energy Expenditure, Obesity, Carbohydrate, Fat, Ketones, Natural History
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: PI is no longer at NIH
- Enrolment
- 5 participants (actual)
- Lead sponsor
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)US National Institutes of Health
- Collaborators
- Pennington Biological Research Center, Translational Research Institute for Metabolism and Diabetes, Columbia University
- Study start
- 3 Dec 2013 (actual)
- Primary completion
- 23 Feb 2015 (actual)
- Study completion
- 23 Feb 2015 (actual)
- First posted
- 23 Oct 2013 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Background:
- Popular weight loss plans often restrict carbohydrates or fat. Research shows that very-low-carbohydrate (ketogenic) diets lead to greater weight loss than low-fat diets. Researchers want to know if eating fewer carbohydrates changes the number of calories the body uses. They also want to know how a ketogenic diet affects hunger, hormones, and food preferences.
Objectives:
- To better understand how the body responds to different diets.
Eligibility:
- Men 18 to 50 years old who are healthy but overweight.
Design:
- Participants will have 3 screening visits:
- Medical history, physical exam, blood test, and EKG. They will eat during the visit.
- For the week before the visit, participants will wear physical activity monitors daily. They will record everything they eat and sample the special diet. At the visit, they will receive an EKG and heart rate test while biking for 30 minutes.
- For the week before the visit, participants will wear the physical activity monitors. They will eat all their meals from the special diet that will be provided. At the visit, they will answer questions and bike for 60 minutes.
- After screening, for 1 week, participants will visit the clinic daily to receive that day s food. They will not eat or drink anything else except water.
- Then participants will stay at the clinic for 8 weeks. They cannot leave but can have visitors. Participants will wear physical activity monitors, bike daily, and follow different diets. Tests will be given daily, and may include weighing, X-rays, and blood and urine tests. They will spend several days in a monitored room to test oxygen and carbon dioxide.
Detailed description
Popular weight loss strategies often prescribe targeted reduction of dietary carbohydrate or fat. Recent clinical trials in obese subjects have found that low-carbohydrate diets result in greater weight loss compared with low-fat diets on a time scale of months when diet adherence was likely the highest. One hypothesis regarding the mechanism of improved weight loss with low carbohydrate diets is that such diets significantly modify the body s hormonal milieu to influence metabolic regulation and energy expenditure. Low-carbohydrate diets may thereby offer a metabolic advantage over low fat diets. In addition, low-carbohydrate diets may also decrease hunger or increase satiety compared to low-fat diets.
Determining the mechanism whereby one diet leads to greater weight loss than another is hampered by the inability to accurately measure food intake or physical activity in an outpatient setting. Thus, an inpatient feeding study lasting many weeks is required to accurately measure energy balance differences between isocaloric diets that differ in macronutrient composition. In this pilot multicenter cross-over study in 16 overweight and class I obese men, we will measure changes in energy expenditure in response to 4 weeks of inpatient feeding of a eucaloric, very low carbohydrate, ketogenic diet (5% Carbohydrate, 15% Protein, 80% Fat) immediately following an inpatient period of at least 4 weeks of consuming an energy balanced standard American diet (50% Carbohydrate, 15 % Protein, 35% Fat).
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| overweight and class I obese adult male volunteers | – | –Adult Male Subjects will be recruited to determine the effects on energy expenditure of transitioning from an energy-and macronutrient-balanced standard baseline diet to a eucaloric ketogenic diet |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- We will study the magnitude and variability of energy expenditure changes in response to a eucaloric ketogenic diet subsequent to a standard energy- and macronutrient-balanced diet in overweight and class I obese adult male volunteers
Key inclusion criteria (9 listed)
- Age 18-50 years, male
- Weight stable (< 5 % over past 6 months)
- Current stable weight no more than 8% below lifetime maximum weight
- Body mass index (BMI) greater than or equal to 25 kg/m(2) but less than 35 kg/m(2), with each study site recruiting an equal number of subjects from the overweight range of 25 kg/m(2) less than or equal to BMI < 30 kg/m(2) and from the class I obese range of 30 kg/m(2) less than or equal to BMI < 35 kg/m(2)
- Otherwise healthy, as determined by medical history and laboratory tests
Key exclusion criteria (12 listed)
- BMI < 25 kg/m(2) or greater than or equal to 35 kg/m(2)
- Blood pressure > 140/90 mm Hg
- Evidence of metabolic or cardiovascular disease, or disease that may influence metabolism (e.g. cancer, diabetes, thyroid disease)
- 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)
- Hematocrit < 40%
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
To determine 24hr energy expenditure, respiratory quotient, and sleeping energy expenditure following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet.
Time frame: 1 year
the subjects will spend the 4th, 5th, 11th, 12th, 18th, 19th, 25th and 26th days of Stages 2 \& 3 in the metabolic chamber to measure 24-hour energy expenditure and sleeping energy expenditure. The energy expenditure calculations will be corrected for urinary ketone excretion since approximately 0.33 L of O2 is consumed for every gram of ketone excreted in the urine.
2 secondary outcomes
To investigate changes in body composition and appetitive behaviors such as hunger, satiety, food impulsivity, and food liking & wanting during a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced stan...
Time frame: 7 days(outpatient) plus 8 weeks( inpatient)
To determine body weight and body composition following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet.
Time frame: 7 days (outpatient) plus 8 weeks (inpatient)
Results and safety
The study was stopped early (reason given: PI is no longer at NIH). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Apr 2025.
- Derived from this study: PubMed 31067015Rosenbaum M, Hall KD, Guo J, Ravussin E, Mayer LS, Reitman ML, Smith SR, Walsh BT, Leibel RL. Glucose and Lipid Homeostasis and Inflammation in Humans Following an Isocaloric Ketogenic Diet. Obesity (Silver Spring). 2019 Jun;27(6):971-981. doi: 10.1002/oby.22468. Epub 2019 May 8.
- Derived from this study: PubMed 31028699Hall KD, Guo J, Chen KY, Leibel RL, Reitman ML, Rosenbaum M, Smith SR, Ravussin E. Methodologic considerations for measuring energy expenditure differences between diets varying in carbohydrate using the doubly labeled water method. Am J Clin Nutr. 2019 May 1;109(5):1328-1334. doi: 10.1093/ajcn/nqy390.
- Derived from this study: PubMed 29761785Koppel N, Bisanz JE, Pandelia ME, Turnbaugh PJ, Balskus EP. Discovery and characterization of a prevalent human gut bacterial enzyme sufficient for the inactivation of a family of plant toxins. Elife. 2018 May 15;7:e33953. doi: 10.7554/eLife.33953.
- Derived from this study: PubMed 27385608Hall KD, Chen KY, Guo J, Lam YY, Leibel RL, Mayer LE, Reitman ML, Rosenbaum M, Smith SR, Walsh BT, Ravussin E. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016 Aug;104(2):324-33. doi: 10.3945/ajcn.116.133561. Epub 2016 Jul 6.
- NIH Clinical Center Detailed Web PageLink provided by the sponsor.
Related trials for Obesity
RecruitingObservational study
Endoscopic Sleeve Gastroplasty (ESG) Prospective Trial for Obesity (EGO-Trial)
Obesity
Active, not recruitingPhase 4
Effects of Sequential Therapy With Mexidol® (Intravenous) and Mexidol® FORTE 250 (Oral) on Functional Brain Activity Assessed by Functional Magnetic Resonance Imaging and Biochemical Parameters in Patients With Chronic Cerebral Ischemia: A Comparison of Patients With and Without Metabolic Disorders
Metabolic Abnormalities, Obesity & Overweight
Recruiting
Exercise Training and Vitamin D Metabolism
Obesity & Overweight, Vitamin D
Recruiting
Metabolic Health, Bones and Nuts During Weight Loss in Adults
Weight Loss, Bone Density
Active, not recruiting
Effect of Probiotics on Insulin Sensitivity in Overweight and Obese Pregnancy
Obesity & Overweight, Gestational Diabetes Mellitus (GDM)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Kevin Hall, Ph.D. principal investigator
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Obesity and Appetite, 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 9 inclusion and 12 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: stopped early, as of the sponsor's last update on 22 Apr 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?
The study was stopped early (reason given: PI is no longer at NIH). Results are not available in the source record.
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?
To determine 24hr energy expenditure, respiratory quotient, and sleeping energy expenditure following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet. (time frame: 1 year). 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 NCT01967563, 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 22 Apr 2025.