NCT05545306 · National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
The Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure
What this study is about
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.
View original scientific description
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. ...
Interventions
DIETARY_SUPPLEMENT
+200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat
+200% of energy balance requirements with standard macronutrient balance of 50% of calories from carbohydrates, 20% from protein, and 30% from fat
DIETARY_SUPPLEMENT
fasting
Fasting for at least 24 hours
DIETARY_SUPPLEMENT
-50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat
-50% of energy balance requirements with standard macronutrient balance of 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
+150% of energy balance requirements with standard macronutrient balance of 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
+200% of energy balance requirements with low protein macronutrient balance of 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
-25% of energy balance (EB) requirements with standard macronutrient balance of 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% of energy balance requirements with low protein macronutrient balance of 51% of the calories from carbohydrates, 46%, from fat and 3% from protein.
Primary outcome measures
Diet Induced Thermogenesis
Time frame: 35 days
DIT is calculated from 24h EE during feeding-24h EE during fasting under different caloric loads
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- In order to be eligible to participate in this study, an individual must meet all of the following criteria:
- Male or female, aged 18-60 years old
- No episodes of intentional weight loss over previous 6 months
Exclusion criteria
- An individual who meets any of the following criteria will be excluded from participation in this study:
- Current use of tobacco products that exceed "Very Low Dependence" on the Fagerstrom Test for Nicotine Dependence Tool (score greater than 2)
- Diabetes i. Fasting glucose \>= 126 mg/dl or hba1c \>= 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 chronic obstructive pulmonary disease 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 hepatitis B or C ii. AST or ALT \>=3 times upper limit of normal on screening labs
- Renal disease i. Serum creatinine \>= 1.5 mg/dls
- Abnormal kidney function (eGFR \<60 mL/min/1.73m\^2)
- 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, HIV chronic coccidiomycosis or other chronic infections
- Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators
- Evidence of alcohol abuse as defined by \> =8-point score on the Alcohol consumption screening AUDIT questionnaire in adults
- Current use of illegal drugs such as amphetamines, cocaine, opiates, or heroin; use of marijuana is permitted.
- For Females:
- i. Pregnancy or lactation by history and urine pregnancy test
- ii. Peri- or post-menopause by self-report or irregular menstrual cycle.
- Measured weight: greater than or equal to 450 lb. (maximum weight allowed on the DXA scanning tables by the manufacturer).
- Inability to speak or read English by self-report.
- Inability to provide informed consent
- History of psychological conditions including (but not limited to) claustrophobia, clinical depression, bipolar disorders, or forms of mental incapacity that would be incompatible with safe and successful participation in this study
- Current use of medications/dietary supplements/alternative therapies known to alter energy metabolism
- Inability to consume provided diets due to dietary concerns that will not allow them to consume \>=95% of provided calories.
Where
- Phoenix, Arizona
Related conditions & keywords
Frequently asked questions
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Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
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Data: ClinicalTrials.gov · synced Jun 11, 2026 · Source of record for eligibility and locations