An interventional study of +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat and fasting in Obesity, Normal Physiology and Healthy Volunteers, sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Recruiting at 1 site in United States. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-28.
Sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Not applicable, Interventional, and Basic science
Background:
Diet-induced thermogenesis (DIT) is the amount of energy one's body uses to eat food, absorb the nutrients from the food, and process those nutrients. Researchers would like to understand more about how changing the balances of protein, fat, carbohydrates, and total calories in the diet can affect DIT.
Objective:
To learn how different diets can change a person's DIT.
Eligibility:
Healthy people aged 18 to 60 years who have not intentionally lost weight in the past 6 months.
Design:
Participants will stay in a clinic for about 35 days. They will eat only the food provided. They will receive 8 different diets during the study, including 7 test diets.
Participants will undergo multiple tests.
They will be screened with blood and urine tests and a test of their heart function.
During the first few days:
Their waist, thigh, and neck circumference will be measured.
They will have a DXA scan: They will lie on a padded table for about 20 minutes while an instrument measures the amount of fat in their body.
They will be tested for diabetes.
They will answer questionnaires about topics including eating behavior, hunger, and stress.
Throughout the study:
Their weight will be measured daily.
Blood tests will be repeated.
They will stay in a metabolic chamber a total of 9 times. They will remain in a closed room for 24 hours while researchers monitor the room temperature and levels of oxygen and carbon dioxide. Participants will collect all their urine for each 24-hour period.
...
Study Description:
Diet-Induced Thermogenesis (DIT) has been reported to increase as a function of the amount caloric intake. This study investigated this dose response between calorie intake and energy expenditure using a single liquid meal. By measuring EE over 24 hours in our respiratory chamber, we can capture the full extent of DIT at different caloric doses in relation to energy balance. Furthermore, we will investigate inter-individual differences in 24hEE response to different calorie loads. This is important as our previous studies demonstrated that individuals with greater EE during energy balance have 1) greater decrease in EE to fasting and 2) blunted EE response to higher calorie loads, in particular those with low protein content, respectively. Briefly, we will make multiple measurements of 24h EE in a whole-room indirect calorimeter, the gold standard measure of metabolism at multiple levels of energy intake relative to energy balance. These measures will be done at energy balance and in random order during fasting, 25, 50, 150 and 200% of energy balance requirements. Macronutrient balance for energy balance and lower calorie diets will be 50% carbohydrate, 30% fat, 20% protein; but for overfeeding will be 3% protein, 46% fat, 51% carbohydrate. The main goals of this research are to examine using state of the art measurement of DIT in a respiratory chamber whether there is indeed an association between caloric intake and energy expenditure and whether inter-individual response to calorie loads differs such that those with higher 24hEE during energy balance, have lower 24hEE during fasting and underfeeding 25 and 50% and lesser response to high calorie loads.
The primary goal of this study is to investigate the impact of relative calorie load on diet-induced thermogenesis.
Objectives:
Primary Objective:
a. To determine whether an association exists between diet-induced thermogenesis, 24hEE and calorie load relative to energy balance.
Secondary Objectives:
Tertiary/Exploratory Objectives:
Endpoints:
Primary Endpoint:
a. Diet induced thermogenesis, as calculated from 24h EE during feeding - 24h EE during fasting under different calorie loads
Secondary Endpoints:
Tertiary/Exploratory Endpoints:
a. Psychosocial assessments, such as food insecurity and perceived stress
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
This study's planned enrollment of 120 is above the median of 67 across 9,006 interventional studies indexed under Obesity.
Browse Obesity studies →National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is the lead sponsor of 538 studies on the registry; 55 are open to participants now.
Of its 80 completed or terminated interventional studies of FDA-regulated products, 51 (64%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
In order to be eligible to participate in this study, an individual must meet all of the following criteria:
EXCLUSION CRITERIA:
An individual who meets any of the following criteria will be excluded from participation in this study:
Diabetes
i. Fasting glucose >= 126 mg/dl or >= 6.5% or
ii. history of type 1 or type 2 diabetes
-Endocrine disorders, such as
i. History of Cushing s disease, pituitary disorders, or hypo- and hyperthyroidism
ii. TSH \<0.1 or >= 10 uIU/mL
Pulmonary disorders
i. History of or other lung disease that which would limit ability to follow the protocol (investigator judgment)
Cardiovascular diseases,
i. Including history of coronary heart disease, heart failure, arrhythmias, and peripheral artery disease
Hypertension,
i. History of diagnosis and current treatment by an outside clinician
ii. or sitting blood pressure measurement, using an appropriate cuff, higher than
140/90 mmHg
-Liver disease,
i. including history of cirrhosis, active or C
ii. or ALT >=3 times on screening labs
Renal disease
i. Serum creatinine >= 1.5 mg/dls
Central nervous system disease:
i. including history of previous history of cerebrovascular accidents, dementia, and neurodegenerative disorders
Cancer:
i. History 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:
i. History of active tuberculosis, chronic coccidiomycosis or other chronic infections
For Females:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
+150% LPF +150% SOF -50% +200% LPF +200% SOF Fasting -25%
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
+200% LPF -25% Fasting +200% SOF -50% +150% LPF +150% SOF
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
+150% LPF +200% LPF -50% +150% SOF Fasting -25% +200% SOF
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
+150% LPF Fasting +150% SOF -25% +200% SOF +200% LPF -50%
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
Fasting -25% +200% LPF -50% +200% SOF +150% SOF +150% LPF
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
-25% +150% SOF +200% LPF +150% LPF Fasting +200% SOF -50%
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
Fasting +200% LPF +200% SOF -50% +150% LPF -25% +150% SOF
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
-50% +200% SOF -25% +150% SOF Fasting +200% LPF +150% LPF
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
-50% +150% SOF +200% SOF +150% LPF -25% +200% LPF Fasting
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
+150% SOF -25% +150% LPF +200% SOF Fasting +200% LPF -50%
Dietary Supplement: +200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: fasting · Dietary Supplement: -50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein · Dietary Supplement: -25% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat · Dietary Supplement: +150% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein
+200% of energy balance requirements with standard macronutrient balance of 50% of calories from carbohydrates, 20% from protein, and 30% from fat
Fasting for at least 24 hours
-50% of energy balance requirements with standard macronutrient balance of 50% of calories from carbohydrates, 20% from protein, and 30% from fat
+150% of energy balance requirements with standard macronutrient balance of 50% of calories from carbohydrates, 20% from protein, and 30% from fat
+200% of energy balance requirements with low protein macronutrient balance of 51% of the calories from carbohydrates, 46%, from fat and 3% from protein.
-25% of energy balance (EB) requirements with standard macronutrient balance of 50% of calories from carbohydrates, 20% from protein, and 30% from fat
+150% of energy balance requirements with low protein macronutrient balance of 51% of the calories from carbohydrates, 46%, from fat and 3% from protein.
Diet Induced Thermogenesis
DIT is calculated from 24h EE during feeding-24h EE during fasting under different caloric loads
Time frame: 35 days
FGF 21
assessment of appetitive hormones before and after 24h in a whole room calorimeter with each intervention
Time frame: 35 days
24 hour energy expenditure (24h EE)
24h EE is measured in a whole room calorimeter
Time frame: 35 days
Substrate Oxidation
24h respiratory quotient measured in a whole room calorimeter
Time frame: 35 days
Psychosocial Assessment
assessment of psychosocial state through assessment of food insecurity and perceived stress
Time frame: 35 days
Ghrelin
assessment of appetitive hormones before and after 24h in a whole room calorimeter with each intervention
Time frame: 35 days
Sympathetic nervous system activity
assessment of changes in urinary catecholamines with each intervention
Time frame: 35 days
Plan to share: Undecided
Started Jun 2023 (actual). Primary completion is estimated for Feb 2027, 43 months after the start.
Of 3,680 non-industry interventional studies with no phase under Obesity, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 43. This study's planned 43 months is above that.
Counting every sponsor, half of 3,843 studies reached it within 22 months; a quarter within 10 and three quarters within 42.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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