An observational study in Healthy Volunteer and Obestity, sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Not yet recruiting at 1 site in United States. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Observational
Background:
Many people in the United States are overweight or obese. This natural history study will look into how life events during childhood can impact eating behaviors and weight gain as adults.
Objective:
To explore how childhood experiences affect adult eating behaviors.
Eligibility:
Healthy people aged 18 to 60 years.
Design:
Participants will have 3 clinic visits.
They will be screened with blood tests. They will answer questions about their alcohol and tobacco use.
At the next visit, participants will undergo these activities:
Parts of their body (such as waist, neck, and thighs) will be measured with a tape.
They will have an imaging scan to find out how much body fat they have.
They will start wearing a device like a wristwatch that measures their physical activity. They will wear this device for up to 10 days.
They will wear a device on their upper arm or belly that measures blood glucose (sugar) levels. Participants will wear this for 7-10 days.
They will answer questions about their education, childhood, and routines.
They will receive a kit to collect a stool sample at home.
At the last visit, participants will have these tests:
Participants will relax and breathe normally while wearing a clear, plastic canopy that fits over their entire head.
Blood samples will be taken before and after participants drink a sugary drink.
Participants will be offered a large selection of foods for lunch. They will eat as much as they want. Then they will answer questions about how they feel about food and themselves.
Study Description:
The unpredictability schema - "a pervasive belief that other people cannot be trusted and future outcomes cannot be predicted or controlled" - has been hypothesized to (1) be shaped by parental/household dynamics and (2) impact appetitive and consumptive behaviors. However, studies on appetitive behaviors were mostly based on self-report and to our knowledge, no studies have examined objective measurements of energy intake or expenditure in association with unpredictability. Therefore, the current study seeks to examine whether the unpredictability schema as measured by a composite score of unpredictability assessments is associated with ad libitum food consumption and eating in the absence of hunger, measured objectively. Furthermore, we will examine the associations between the unpredictability schema and physical activity, resting metabolic rate/respiratory quotient, and glucose trajectories during an oral glucose tolerant test and continuous glucose monitoring in a cohort of healthy participants.
Objectives:
Primary Objective:
Secondary Objectives:
Tertiary Objectives:
Endpoints:
Primary Endpoint:
Secondary Endpoints:
Tertiary Endpoints:
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
This study's planned enrollment of 110 is close to the median of 114 across 2,154 observational 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.
The study will enroll healthy, non-pregnant, women and men aged 18-60 years old who are without diabetes from the Greater Phoenix area, Arizona, United States. The study anticipates screening/enrolling 310 participants to achieve a goal of 110 participants completing the study.
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
Endocrine disorders, such as
--Self-reported history of Cushing's disease, pituitary disorders, or hypo- and hyperthyroidism
Pulmonary disorders
--Self-reported history of or other lung disease that which would limit ability to follow the protocol (investigator judgment)
Cardiovascular diseases,
--Self-reported history of coronary heart disease, heart failure, arrhythmias, and peripheral artery disease that which would limit ability to follow the protocol (investigator judgment)
Liver disease,
Gastrointestinal Surgery
--Self-reported history of bariatric surgery
Renal disease
Central nervous system disease:
--Including self-reported history of previous history of cerebrovascular accidents, dementia, and neurodegenerative disorders
Infectious disease:
--Self-reported history of active tuberculosis, , chronic coccidiomycosis or other chronic or acute infections
Non-English-speaking subjects as a population will be excluded from participation in this protocol. Primary and secondary hypotheses of the protocol relate to a battery of psychological questionnaires and performances tests which are administered throughout the study. There are currently no validated, translated forms of these questionnaires and tests available; therefore, we will restrict enrollment to English speaking subjects only.
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.
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
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.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
adults, age 18-60 years
To determine whether an association exists between unpredictability schema measures and ad libitum food intake.
Ad libitum Food Intake (kcal) measured from a buffet meal task.
Time frame: Day 10
To determine whether an association exists between the unpredictability schema and experience scores and eating in the absence of hunger
Eating in the absence of hunger (kcal) from a snack food taste test.
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores and physical activity.
Physical activity values and trajectories from the 10-day outpatient research accelerometer assessment
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores and resting metabolic rate and RQ.
Resting metabolic rate and respiratory quotient values obtained from the metabolic hood.
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores and glucose values (CGM and OGTT)
Glucose values and trajectories from fasting labs, OGTT, and 10-day outpatient CGM assessment, including mean, standard deviation, area-under-the-curve, and estimated a1c
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores and telomere length
Telomere length (t/s ratio)
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores and with gut microbiota composition.
Gut Flora Composition
Time frame: Day 10
To determine whether an association exists between measures of the unpredictability schema and experience scores with county-level food swamp statistics (i.e., Retail Food Environment Index).
County-level Food Swamp Score (i.e., Retail Food Environment Index)
Time frame: Day 10
To determine whether an association exists between the unpredictability schema and experience scores and self-reported appetitive eating traits and behavior
Self-reported scores from the following eating measures: Eating in the Absence of Hunger Scale, Body Awareness Questionnaire, Reward-Based Eating Drive Scale, U.S. Adult food Security Survey Module, and the Three-Factor Eating Questionnaire.
Time frame: Day 10
Plan to share: No
Start is estimated for Nov 2026; primary completion for Jan 2027, 2 months later.
Of 791 non-industry observational studies under Obesity, half reached primary completion within 40 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 106. This study's planned 2 months is below that.
Counting every sponsor, half of 836 studies reached it within 39 months; a quarter within 17 and three quarters within 96.
Start moved 32 times since we started tracking on Sep 25, 2026: Sep 2026 → Nov 2026, last on Nov 10, 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) →