Recruiting

Caloric IntakeThe Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure

Sponsor:

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Code:

NCT05545306

Conditions

Obesity

Normal Physiology

Healthy Volunteers

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

Interventions

+200% of dietary requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat

fasting

-50% of energy balance requirements. 50% of calories from carbohydrates, 20% from protein, and 30% from fat

+150% of energy balance requirements, 50% of calories from carbohydrates, 20% from protein, and 30% from fat

+200% of dietary requirements, 51% of the calories from carbohydrates, 46%, from fat and 3% from protein

Study Details

Brief summary:

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.

...

Conditions

Obesity

Normal Physiology

Healthy Volunteers

Study ID

NCT05545306

Start date

Jun 6, 2023

Status verified date

Aug 26, 2026

Completion date

Feb 2, 2027

Anticipated

Primary completion date

Feb 2, 2027

Anticipated

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Accepted

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.

Study Design

Enrollment

120 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

active comparator: Set 1

+150% LPF +150% SOF -50% +200% LPF +200% SOF Fasting -25%

active comparator: Set 10

+200% LPF -25% Fasting +200% SOF -50% +150% LPF +150% SOF

active comparator: Set 2

+150% LPF +200% LPF -50% +150% SOF Fasting -25% +200% SOF

active comparator: Set 3

+150% LPF Fasting +150% SOF -25% +200% SOF +200% LPF -50%

active comparator: Set 4

Fasting -25% +200% LPF -50% +200% SOF +150% SOF +150% LPF

active comparator: Set 5

-25% +150% SOF +200% LPF +150% LPF Fasting +200% SOF -50%

active comparator: Set 6

Fasting +200% LPF +200% SOF -50% +150% LPF -25% +150% SOF

active comparator: Set 7

-50% +200% SOF -25% +150% SOF Fasting +200% LPF +150% LPF

active comparator: Set 8

-50% +150% SOF +200% SOF +150% LPF -25% +200% LPF Fasting

active comparator: Set 9

+150% SOF -25% +150% LPF +200% SOF Fasting +200% LPF -50%

Interventions

+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

fasting

Fasting for at least 24 hours

-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

+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

+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.

-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

+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 measure

Diet Induced Thermogenesis [ Time Frame: 35 days ]

Central Contacts and Locations

Central contacts

Office of Participant Recruitment (NIDDK

(602) 200-5315 niddkphxcontact@mail.nih.gov

Tomas Cabeza De Baca, Ph.D.

(301) 496-9404 tommy.cabezadebaca@nih.gov

Locations

NIDDK, Phoenix

Recruiting

Phoenix, Arizona, United States, 85004

Contacts

Office of Participant Recruitment-NIDDK

602-200-5315 niddkphxcontact@mail.nih.gov

More Information

Sponsor

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Last update posted

Aug 28, 2026

Last verified

Aug 26, 2026

Keywords

Weight Gain
Energy Expenditure
Low Protein Overfeeding
Fasting
Natural History

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) on 2026-08-28.