ObesityNCT00523627
Effects of Diet Changes on Metabolism
An observational study of Obesity, run by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) at 1 site in United States.
Trial summary
This study, conducted at the NIH Clinical Research Unit at the Phoenix Indian Medical Center, will examine how the body s metabolism (energy expenditure) changes when people overeat and when they fast and how different diets (e.g., high-protein or high-fat) affect metabolism. Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- Obesity
- How many people
- 203 participants
- Where
- 1 siteUnited States
- Study dates
- 22 May 2008to not given
- 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 55 years
- All sexes
- No healthy volunteers
- Adult
Study population: Residents of the Phoenix metropolitan area
Who may be able to join
- Age: 18-55 years, to exclude effects of aging on energy expenditure and weight change. For the PET-CT substudy, women will be limited to ages 18-40 years because there is a high likelihood that for women greater than 40 years, their personal physician may recommend an annual routine mammogram, thereby increasing their annual radiation exposure. Men will also be limited to this age range to prevent age discrepancies between men and women for this substudy.
- Premenopausal
- Weight: less than or equal to 450 lb (maximum weight allowed on the DXA scanning tables by the manufacturer).
Who cannot join
- History or clinical manifestation of:
- Current smoking
- Impaired glucose tolerance (IGT), type 1 and type 2 diabetes
- Endocrine disorders, such as Cushing s disease, pituitary disorders, and hypo- and hyperthyroidism
- Pulmonary disorders, including chronic obstructive pulmonary disease, which would limit ability to follow the protocol (investigator judgment)
- Cardiovascular diseases, including coronary heart disease, heart failure, arrhythmias, and peripheral artery disease
Show all 18Show fewer
- Hypertension, as diagnosed and treated by an outside physician or by sitting blood pressure measurement, using an appropriate cuff, higher than 140/90 mmHg on two or more occasions
- Liver disease, including cirrhosis, active hepatitis B or C, and AST or ALT greater than or equal to 3 times normal
- Renal disease, as defined by serum creatinine concentrations greater than or equal 1.5 mg/dl and/or proteinuria greater than 300 mg/day (200 (Micro)g/min)
- Central nervous system disease, including previous history of cerebrovascular accidents, dementia, and neurodegenerative disorders
- Cancer requiring treatment in the past five years, except for non-melanoma skin cancers or cancers that have clearly been cured or in the opinion of the investigator carry an excellent prognosis (e.g., Stage 1 cervical cancer).
- Infectious disease such as active tuberculosis, HIV (by self-report), chronic coccidiomycoses or other chronic infections that might influence weight.
- Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators
- Alcohol and/or drug abuse (more than 3 drinks per day and use of drugs, such as amphetamines, cocaine, heroin, or marijuana).
- Pregnancy or lactation
- For the PET-CT substudy, radiation exposure to the torso for research or medical purposes within the past 12 months
- Positive Urinalysis Drug Screen
- Prior to beginning any of the study procedures, all subjects will be fully informed of the aim, nature, and risks of the study prior to giving written informed consent. The study s informed consent will be obtained by a principal or associate investigator, research physician or physician assistant working in the clinical research unit.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Study of Short-Term Metabolic Adaptation: Prediction of Weight Change and Effects of Macronutrient Manipulations
This study, conducted at the NIH Clinical Research Unit at the Phoenix Indian Medical Center, will examine how the body s metabolism (energy expenditure) changes when people overeat and when they fast and how different diets (e.g., high-protein or high-fat) affect metabolism. The results may provide information about whether there are mechanisms that make some people more resistant than others to gaining weight when they eat more.
Non-smoking healthy subjects between 18 and 55 years of age who weigh no more than 350 pounds may be eligible for this study. Participants undergo the following procedures:
Read more
- Pregnancy test for women of childbearing age.
- Oral glucose tolerance test. For this test, an I.V. line (needle attached to a plastic tube) is inserted into a vein to allow several blood draws without repeated needle sticks. After the first blood sample is drawn, the subject drinks a cola-flavored sugar solution. Five additional blood samples are then drawn over 3 hours.
- Blood test for DNA (genetic) studies related to obesity, diabetes and related medical problems.
- DEXA scan. This test measures body fat. The subject lies on a table while a very small dose of X-rays is passed through the body.
- Respiratory chamber. This test measures how many calories the body burns a day and assesses energy balance between intake and expenditure. Subjects stay in a room with two windows, equipped with a sink, toilet, television and DVD player, desk, chair, telephone and bed for 24 hours. The test is repeated five times during the first 18-day admission and 3 times during the second 13-day admission. For the first two sessions, subjects are fed a diet equal to the amount of energy their body uses. For the next 6 stays they are fed double the amount of calories their body usually uses for 5 of the stays and fast (consume nothing but water and soda without caffeine or calories) during 1 stay. The overfeeding diets may be high or low in protein, normal in protein, or high in fat. Blood tests are done on the day of each respiratory chamber session and a 24-hour urine sample is collected for one day while in the chamber.
- Eating behavior questionnaires.
- Psychological performance tests.
Some participants are asked to volunteer to repeat two of the chamber studies to validate the measurements. The repeat session includes only the fasting and the overfeeding with normal protein content.
All participants are followed at 6 months with blood tests, a DEXA scan, and urine tests (including pregnancy test for women). At annual visits for years 1 through 7, participants have the 6-month tests plus an oral glucose tolerance test.
Read the detailed description
Some people appear to be more resistant than others to gaining weight when they overeat, though they do not increase their physical activity. This may indicate that adaptive mechanisms exist, which lead to wasting as heat part of the excess calories taken in. Such mechanisms exist in rodents including activation of brown fat, a tissue which can also convert calories to heat for warmth. Human studies have provided conflicting results. A pilot study on the relationship of the weight change over time with the changes in the amount of energy an individual uses over 24 hours (energy expenditure, EE) with 48-h overfeeding (OF) and fasting (F) in Pima Indian men has shown that persons with the greatest increase in EE with OF and the smallest decrease in EE with F gained the least weight over time, indicating that the ability to waste more calories when overfed may reduce weight gain. Other studies, however, have not shown this relationship. In addition, it has been proposed that unbalanced diets can help magnify these effects. The aims of this study are to test whether (a) the changes in EE in response to 24-h OF and F predict changes in weight over two years, and (b) high-carbohydrate diets or diets with high or low protein amounts may magnify the metabolic response to 24-h OF compared to normal protein and high-fat diets. 86 volunteers will be evaluated at baseline, 6 months and on a yearly basis for up to 7 years. At baseline, subjects will undergo 8 24-h sessions in a human respiratory chamber to measure EE while on a weight-maintaining diet, and then in random order: fasting, 200% OF on a normal-protein diet, 200% OF on a high fat, low-protein diet, 200% OF on a high-fat, normal-protein diet, 200% OF on a high fat, high protein diet, and 200% OF on a high-carbohydrate, normal-protein diet. Fifteen volunteers will have two additional chambers to try and understand if the source of carbohydrates, i.e. simple sugars versus complex carbohydrates, in a high carbohydrate diet affect metabolism. Thirty volunteers are planned to also undergo 2 positron emission tomography (PET) studies to look at the relationship of brown fat with EE in adult humans. (As of April 2021, we will stop performing the PET scans; 24 volunteers have completed them and we have acquired sufficient data.) Body weight and composition will be measured at each subsequent admission. Hormonal measurements to find determinants of adaptive changes in EE in response to OF and F will also be performed. This study will provide significant insights into possible mechanisms that may help people resist weight gain and obesity.
- Conditions
- Obesity
- Keywords
- Energy Expenditure, Adaptive Thermogenesis, Low-protein Overfeeding, Fasting, Weight Gain, Natural History
- Medical subject headings
- Obesity, Fasting, Weight Gain
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 |
|---|---|---|
| Healthy Volunteers with normal glucose regulation | Healthy volunteers with normal glucose regulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Weight, DXA scans, resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Changes in body weight and composition in response to changes in energy expenditure
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Weight, DXA scans
Changes in body weight and composition in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Changes in energy expenditure in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Secondary outcomes (7)
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, FDG-PET and FDG-CT scans, core body and distal skin temperature
Changes in BAT levels in response to cool temperature (16 degrees C), changes in energy expenditure, or changes in diet
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature, questionnaires
Predictive value of substrate oxidation in chambers for changes in appetite sensations upon completion of 24 hour respiratory chamber
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Repeatability of changes in energy expenditure in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Effect of simple sugars and complex carbohydrates during overfeeding on energy expenditure
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Changes in energy expenditure response to overfeeding in response to thermal insulation of the body core
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Hormone values in blood and urine,
Changes in hormones involved in the regulation of energy metabolism in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Core body and distal skin temperature
Changes in thermic effect of food during overfeeding in response to beta blockade
Measured: at baseline visit, 6 month visit, and then annually for up to 7 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Aug 2007 (estimated)
- Study start22 May 2008
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (17)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
- 203 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Tomas Cabeza De Baca, Ph.D., Principal investigator, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00523627
- Sponsor's protocol ID
- 999907215
- Other IDs
- 07-DK-N215
- Status last verified
- 6 Feb 2026
- First submitted
- 30 Aug 2007
- Last updated
- 26 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Trevino-Alvarez AM, Cabeza de Baca T, Stinson EJ, Gluck ME, Chang DC, Piaggi P, Krakoff J. Greater anhedonia scores in healthy individuals are associated with less decline in 24-hour energy expenditure with fasting: Evidence for a link between behavioral traits and spendthrift phenotype. Physiol Behav. 2023 Oct 1;269:114281. doi: 10.1016/j.physbeh.2023.114281. Epub 2023 Jun 24.
PubMed 37356515Hollstein T, Basolo A, Unlu Y, Ando T, Walter M, Krakoff J, Piaggi P. Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype. J Clin Endocrinol Metab. 2022 Aug 18;107(9):e3769-e3780. doi: 10.1210/clinem/dgac353.
PubMed 35678263Hollstein T, Basolo A, Ando T, Krakoff J, Piaggi P. Reduced adaptive thermogenesis during acute protein-imbalanced overfeeding is a metabolic hallmark of the human thrifty phenotype. Am J Clin Nutr. 2021 Oct 4;114(4):1396-1407. doi: 10.1093/ajcn/nqab209.
PubMed 34225360Hollstein 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 32118268Hollstein T, Basolo A, Ando T, Votruba SB, Krakoff J, Piaggi P. Urinary Norepinephrine Is a Metabolic Determinant of 24-Hour Energy Expenditure and Sleeping Metabolic Rate in Adult Humans. J Clin Endocrinol Metab. 2020 Apr 1;105(4):1145-56. doi: 10.1210/clinem/dgaa047.
PubMed 32002540Begaye B, Vinales KL, Hollstein T, Ando T, Walter M, Bogardus C, Krakoff J, Piaggi P. Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain in Healthy Adults. Diabetes. 2020 Feb;69(2):181-192. doi: 10.2337/db19-0719. Epub 2019 Nov 11.
PubMed 31712321Piaggi P. Metabolic Determinants of Weight Gain in Humans. Obesity (Silver Spring). 2019 May;27(5):691-699. doi: 10.1002/oby.22456.
PubMed 31012296Vinales KL, Begaye B, Thearle MS, Krakoff J, Piaggi P. Core body temperature, energy expenditure, and epinephrine during fasting, eucaloric feeding, and overfeeding in healthy adult men: evidence for a ceiling effect for human thermogenic response to diet. Metabolism. 2019 May;94:59-68. doi: 10.1016/j.metabol.2019.01.016. Epub 2019 Jan 31.
PubMed 30710573Stinson EJ, Graham AL, Thearle MS, Gluck ME, Krakoff J, Piaggi P. Cognitive dietary restraint, disinhibition, and hunger are associated with 24-h energy expenditure. Int J Obes (Lond). 2019 Jul;43(7):1456-1465. doi: 10.1038/s41366-018-0305-9. Epub 2019 Jan 16.
PubMed 30651576Begaye B, Piaggi P, Thearle MS, Haskie K, Walter M, Schlogl M, Bonfiglio S, Krakoff J, Vinales KL. Norepinephrine and T4 Are Predictors of Fat Mass Gain in Humans With Cold-Induced Brown Adipose Tissue Activation. J Clin Endocrinol Metab. 2018 Jul 1;103(7):2689-2697. doi: 10.1210/jc.2018-00387.
PubMed 29788444Stinson EJ, Krakoff J, Gluck ME. Depressive symptoms and poorer performance on the Stroop Task are associated with weight gain. Physiol Behav. 2018 Mar 15;186:25-30. doi: 10.1016/j.physbeh.2018.01.005. Epub 2018 Jan 9.
PubMed 29326031Vinales KL, Schlogl M, Reinhardt M, Thearle MS, Krakoff J, Piaggi P. Cycling Efficiency During Incremental Cycle Ergometry After 24 Hours of Overfeeding or Fasting. Obesity (Silver Spring). 2018 Feb;26(2):368-377. doi: 10.1002/oby.22096. Epub 2017 Dec 25.
PubMed 29276860Ibrahim M, Bonfiglio S, Schlogl M, Vinales KL, Piaggi P, Venti C, Walter M, Krakoff J, Thearle MS. Energy Expenditure and Hormone Responses in Humans After Overeating High-Fructose Corn Syrup Versus Whole-Wheat Foods. Obesity (Silver Spring). 2018 Jan;26(1):141-149. doi: 10.1002/oby.22068. Epub 2017 Nov 28.
PubMed 29193741Vinales KL, Schlogl M, Piaggi P, Hohenadel M, Graham A, Bonfiglio S, Krakoff J, Thearle MS. The Consistency in Macronutrient Oxidation and the Role for Epinephrine in the Response to Fasting and Overfeeding. J Clin Endocrinol Metab. 2017 Jan 1;102(1):279-289. doi: 10.1210/jc.2016-3006.
PubMed 27820654Ibrahim M, Thearle MS, Krakoff J, Gluck ME. Perceived stress and anhedonia predict short-and long-term weight change, respectively, in healthy adults. Eat Behav. 2016 Apr;21:214-9. doi: 10.1016/j.eatbeh.2016.03.009. Epub 2016 Mar 3.
PubMed 27002703
Study at a glance
From the registry record, last updated by the sponsor on 26 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study of Short-Term Metabolic Adaptation: Prediction of Weight Change and Effects of Macronutrient Manipulations
- ClinicalTrials.gov ID
- NCT00523627
- Acronym / sponsor ID
- 999907215
- Conditions
- Obesity
- Keywords
- Energy Expenditure, Adaptive Thermogenesis, Low-protein Overfeeding, Fasting, Weight Gain, Natural History
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 203 participants (actual)
- Lead sponsor
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)US National Institutes of Health
- Study start
- 22 May 2008 (actual)
- First posted
- 31 Aug 2007 (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.
This study, conducted at the NIH Clinical Research Unit at the Phoenix Indian Medical Center, will examine how the body s metabolism (energy expenditure) changes when people overeat and when they fast and how different diets (e.g., high-protein or high-fat) affect metabolism. The results may provide information about whether there are mechanisms that make some people more resistant than others to gaining weight when they eat more.
Non-smoking healthy subjects between 18 and 55 years of age who weigh no more than 350 pounds may be eligible for this study. Participants undergo the following procedures:
- Pregnancy test for women of childbearing age.
- Oral glucose tolerance test. For this test, an I.V. line (needle attached to a plastic tube) is inserted into a vein to allow several blood draws without repeated needle sticks. After the first blood sample is drawn, the subject drinks a cola-flavored sugar solution. Five additional blood samples are then drawn over 3 hours.
- Blood test for DNA (genetic) studies related to obesity, diabetes and related medical problems.
- DEXA scan. This test measures body fat. The subject lies on a table while a very small dose of X-rays is passed through the body.
- Respiratory chamber. This test measures how many calories the body burns a day and assesses energy balance between intake and expenditure. Subjects stay in a room with two windows, equipped with a sink, toilet, television and DVD player, desk, chair, telephone and bed for 24 hours. The test is repeated five times during the first 18-day admission and 3 times during the second 13-day admission. For the first two sessions, subjects are fed a diet equal to the amount of energy their body uses. For the next 6 stays they are fed double the amount of calories their body usually uses for 5 of the stays and fast (consume nothing but water and soda without caffeine or calories) during 1 stay. The overfeeding diets may be high or low in protein, normal in protein, or high in fat. Blood tests are done on the day of each respiratory chamber session and a 24-hour urine sample is collected for one day while in the chamber.
- Eating behavior questionnaires.
- Psychological performance tests.
Some participants are asked to volunteer to repeat two of the chamber studies to validate the measurements. The repeat session includes only the fasting and the overfeeding with normal protein content.
All participants are followed at 6 months with blood tests, a DEXA scan, and urine tests (including pregnancy test for women). At annual visits for years 1 through 7, participants have the 6-month tests plus an oral glucose tolerance test.
Detailed description
Some people appear to be more resistant than others to gaining weight when they overeat, though they do not increase their physical activity. This may indicate that adaptive mechanisms exist, which lead to wasting as heat part of the excess calories taken in. Such mechanisms exist in rodents including activation of brown fat, a tissue which can also convert calories to heat for warmth. Human studies have provided conflicting results. A pilot study on the relationship of the weight change over time with the changes in the amount of energy an individual uses over 24 hours (energy expenditure, EE) with 48-h overfeeding (OF) and fasting (F) in Pima Indian men has shown that persons with the greatest increase in EE with OF and the smallest decrease in EE with F gained the least weight over time, indicating that the ability to waste more calories when overfed may reduce weight gain. Other studies, however, have not shown this relationship. In addition, it has been proposed that unbalanced diets can help magnify these effects. The aims of this study are to test whether (a) the changes in EE in response to 24-h OF and F predict changes in weight over two years, and (b) high-carbohydrate diets or diets with high or low protein amounts may magnify the metabolic response to 24-h OF compared to normal protein and high-fat diets. 86 volunteers will be evaluated at baseline, 6 months and on a yearly basis for up to 7 years. At baseline, subjects will undergo 8 24-h sessions in a human respiratory chamber to measure EE while on a weight-maintaining diet, and then in random order: fasting, 200% OF on a normal-protein diet, 200% OF on a high fat, low-protein diet, 200% OF on a high-fat, normal-protein diet, 200% OF on a high fat, high protein diet, and 200% OF on a high-carbohydrate, normal-protein diet. Fifteen volunteers will have two additional chambers to try and understand if the source of carbohydrates, i.e. simple sugars versus complex carbohydrates, in a high carbohydrate diet affect metabolism. Thirty volunteers are planned to also undergo 2 positron emission tomography (PET) studies to look at the relationship of brown fat with EE in adult humans. (As of April 2021, we will stop performing the PET scans; 24 volunteers have completed them and we have acquired sufficient data.) Body weight and composition will be measured at each subsequent admission. Hormonal measurements to find determinants of adaptive changes in EE in response to OF and F will also be performed. This study will provide significant insights into possible mechanisms that may help people resist weight gain and obesity.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy Volunteers with normal glucose regulation | – | –Healthy volunteers with normal glucose regulation |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
- Study population
- Residents of the Phoenix metropolitan area
Key inclusion criteria (3 listed)
- Age: 18-55 years, to exclude effects of aging on energy expenditure and weight change. For the PET-CT substudy, women will be limited to ages 18-40 years because there is a high likelihood that for women greater than 40 years, their personal physician may recommend an annual routine mammogram, thereby increasing their annual radiation exposure. Men will also be limited to this age range to prevent age discrepancies between men and women for this substudy.
- Premenopausal
- Weight: less than or equal to 450 lb (maximum weight allowed on the DXA scanning tables by the manufacturer).
Key exclusion criteria (18 listed)
- History or clinical manifestation of:
- Current smoking
- Impaired glucose tolerance (IGT), type 1 and type 2 diabetes
- Endocrine disorders, such as Cushing s disease, pituitary disorders, and hypo- and hyperthyroidism
- Pulmonary disorders, including chronic obstructive pulmonary disease, which would limit ability to follow the protocol (investigator judgment)
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
Weight, DXA scans, resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Changes in body weight and composition in response to changes in energy expenditure
Weight, DXA scans
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Changes in body weight and composition in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Changes in energy expenditure in response to overfeeding and fasting diets with high, normal, or low levels of carbohydrates, protein, or fat
7 secondary outcomes
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, FDG-PET and FDG-CT scans, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature, questionnaires
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Hormone values in blood and urine,
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Core body and distal skin temperature
Time frame: at baseline visit, 6 month visit, and then annually for up to 7 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Oct 2026.
- Derived from this study: PubMed 37356515Trevino-Alvarez AM, Cabeza de Baca T, Stinson EJ, Gluck ME, Chang DC, Piaggi P, Krakoff J. Greater anhedonia scores in healthy individuals are associated with less decline in 24-hour energy expenditure with fasting: Evidence for a link between behavioral traits and spendthrift phenotype. Physiol Behav. 2023 Oct 1;269:114281. doi: 10.1016/j.physbeh.2023.114281. Epub 2023 Jun 24.
- Derived from this study: PubMed 35678263Hollstein T, Basolo A, Unlu Y, Ando T, Walter M, Krakoff J, Piaggi P. Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype. J Clin Endocrinol Metab. 2022 Aug 18;107(9):e3769-e3780. doi: 10.1210/clinem/dgac353.
- Derived from this study: PubMed 34225360Hollstein T, Basolo A, Ando T, Krakoff J, Piaggi P. Reduced adaptive thermogenesis during acute protein-imbalanced overfeeding is a metabolic hallmark of the human thrifty phenotype. Am J Clin Nutr. 2021 Oct 4;114(4):1396-1407. doi: 10.1093/ajcn/nqab209.
- Derived from this study: PubMed 32118268Hollstein 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.
- Derived from this study: PubMed 32002540Hollstein T, Basolo A, Ando T, Votruba SB, Krakoff J, Piaggi P. Urinary Norepinephrine Is a Metabolic Determinant of 24-Hour Energy Expenditure and Sleeping Metabolic Rate in Adult Humans. J Clin Endocrinol Metab. 2020 Apr 1;105(4):1145-56. doi: 10.1210/clinem/dgaa047.
- Derived from this study: PubMed 31712321Begaye B, Vinales KL, Hollstein T, Ando T, Walter M, Bogardus C, Krakoff J, Piaggi P. Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain in Healthy Adults. Diabetes. 2020 Feb;69(2):181-192. doi: 10.2337/db19-0719. Epub 2019 Nov 11.
- Derived from this study: PubMed 31012296Piaggi P. Metabolic Determinants of Weight Gain in Humans. Obesity (Silver Spring). 2019 May;27(5):691-699. doi: 10.1002/oby.22456.
- Derived from this study: PubMed 30710573Vinales KL, Begaye B, Thearle MS, Krakoff J, Piaggi P. Core body temperature, energy expenditure, and epinephrine during fasting, eucaloric feeding, and overfeeding in healthy adult men: evidence for a ceiling effect for human thermogenic response to diet. Metabolism. 2019 May;94:59-68. doi: 10.1016/j.metabol.2019.01.016. Epub 2019 Jan 31.
- Derived from this study: PubMed 30651576Stinson EJ, Graham AL, Thearle MS, Gluck ME, Krakoff J, Piaggi P. Cognitive dietary restraint, disinhibition, and hunger are associated with 24-h energy expenditure. Int J Obes (Lond). 2019 Jul;43(7):1456-1465. doi: 10.1038/s41366-018-0305-9. Epub 2019 Jan 16.
- Derived from this study: PubMed 29788444Begaye B, Piaggi P, Thearle MS, Haskie K, Walter M, Schlogl M, Bonfiglio S, Krakoff J, Vinales KL. Norepinephrine and T4 Are Predictors of Fat Mass Gain in Humans With Cold-Induced Brown Adipose Tissue Activation. J Clin Endocrinol Metab. 2018 Jul 1;103(7):2689-2697. doi: 10.1210/jc.2018-00387.
- Derived from this study: PubMed 29326031Stinson EJ, Krakoff J, Gluck ME. Depressive symptoms and poorer performance on the Stroop Task are associated with weight gain. Physiol Behav. 2018 Mar 15;186:25-30. doi: 10.1016/j.physbeh.2018.01.005. Epub 2018 Jan 9.
- Derived from this study: PubMed 29276860Vinales KL, Schlogl M, Reinhardt M, Thearle MS, Krakoff J, Piaggi P. Cycling Efficiency During Incremental Cycle Ergometry After 24 Hours of Overfeeding or Fasting. Obesity (Silver Spring). 2018 Feb;26(2):368-377. doi: 10.1002/oby.22096. Epub 2017 Dec 25.
- Individual participant dataSharing planned: Undecided
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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.
Tomas Cabeza De Baca, 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, 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 3 inclusion and 18 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 26 Oct 2026. 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 is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Weight, DXA scans, resting metabolic rate, thermic effect of food, energy cost of physical activity, cycle ergometry, core body and distal skin temperature (time frame: at baseline visit, 6 month visit, and then annually for up to 7 years). The study lists 3 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 NCT00523627, which also lists 17 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 26 Oct 2026.