Clinical Trials

Open studies conducted by NIDDK Principal Investigators appear below. Study statuses may include the following:

  • Open: Recruiting - Currently recruiting participants and open to everyone who meets eligibility criteria.
  • Open: Active, Not Recruiting - Participants are receiving an intervention or being examined, however new participants are not being recruited or enrolled.
  • Open: Enrolling by Invitation - People in a particular population were selected in advance and invited to participate. The study is not open to everyone who meets the eligibility criteria.
  • Open: Available for Expanded Access - Patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.

Studies Seeking Patients

Variability In Mixed Meal Tests: Fixed Versus Adjusted to Energy Needs Caloric Dose

Background: Researchers use mixed meal tolerance tests (MMTTs) to look at how people s bodies respond to eating a meal. However, researchers do not agree on how to decide the number of calories to give in each meal. Some use fixed meals, which are the same size for everyone, and some use adjusted meals, based on the size of the person s body. Researchers want to know which MMTT is best to use for future research. Objective: To learn how fixed vs adjusted meals affect blood glucose levels in healthy people. Eligibility: Healthy people aged 18 years or older. Design: Participants will have 3 or 4 clinic visits of up to 8 hours in 8 weeks. Participants will have baseline tests: Their height, weight, and waist size will be measured. They will have an oral glucose tolerance test: A needle attached to a tube (IV) will be inserted into a vein in the arm. They will have a sugary drink. Blood samples will be taken from the tube at intervals up to 3 hours after the drink. They will have a body scan. Participants will have 2 MMTT visits. One will include a fixed meal and one will include an adjusted meal. They will have tests at both visits: Resting metabolic rate: A clear hood will be placed over the participant s head while they rest for 20 minutes. This will measure the oxygen they breathe in and out. MMTT. Participants will have 5 minutes to drink a liquid meal. Blood samples will be taken at intervals for the next 4 hours....

The trial is Open with a status of Recruiting.

Investigator: Susi M Votruba, Ph.D.

Referral Contacts: (602) 200-5336

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

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 34 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. ...

The trial is Open with a status of Recruiting.

Investigator: Tomas Cabeza De Baca

Referral Contacts: (602) 200-5315

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The Impact of the COVID-19 Pandemic on Eating Behavior and Weight Change

Background: The indirect effects of the COVID-19 pandemic on mental health are of increasing concern. Perceived stress can lead to binge eating and weight gain. Researchers want to learn more about the relationship between eating behavior and the pandemic. Objective: To study how the stress of the COVID-19 pandemic is affecting eating behaviors and weight. Eligibility: English-speaking adults ages 18 and older who have access to a computer or smartphone connected to the internet. Design: This is an online study. Participants will answer surveys through the study website. Participants will complete a one-time survey. It will ask about their experiences throughout the COVID-19 pandemic, their socioeconomic standing, their mental and physical health, and their eating habits. They will have the option to repeat the survey once a month for the next 12 months. This will show changes in their thoughts and behaviors over time. They will provide their email address to get survey links. Participants will also have the option to complete a 2-minute survey on their smartphone. They will complete the survey daily for 7 days in a row. It will ask about their stress and eating behavior in real time, in their home environment. They will provide their phone number to get survey links via text message. If a participant has taken part in a previous NIH study on the Phoenix AZ campus, they will be asked to share their first and last name, date of birth, and email address. This information will be used to connect data from this study to their past data. Participation is typically 25 minutes but may last up to 1 year. ***To participate in this study go to the REDCap study link: https://redcap.link/nihcovidstudy.***...

The trial is Open with a status of Active, not recruiting.

Investigator: Marci E Gluck, Ph.D.

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Developing Biomarkers of Dietary Intake: Dose Dependent Measurement of Sugar Intake

Background: Diet is one of the most modifiable behaviors affecting health. But diet assessment measures that are based on self-report can be inaccurate. Researchers want better ways to address the role of diet in chronic disease. They want to see if stable isotopes can be used to better assess what people eat. Objective: To see if stable isotopes can help scientists identify things people eat. Eligibility: Healthy adults ages 18 to 65 Design: Participants will be screened with a medical history and physical exam. They will have blood and urine tests. These tests will be repeated during the study. Participants will stay in the inpatient unit of the NIH in Phoenix, Arizona, for 13 weeks. For 7 days, participants will eat a diet prepared by the NIH kitchen. They will get balanced meals that are 50% carbohydrates, 20% protein, and 30% fat. Then participants will be randomly placed on one of 3 diets containing different percentages of carbohydrates from soda. Participants height and weight will be measured. The amount of fat and muscle in their body will be measured by body scans that are similar to x-rays. Participants will have oral glucose tolerance tests. They will consume a sugar drink and then give blood samples over 3 hours. Participants will give hair and stool samples. Participants will complete a diet questionnaire. It assesses their food intake over 24 hours. Participants will complete behavioral questionnaires and computer performance tests. Participants will have fat biopsies taken from their stomach and thigh. Participants will have three 24-hour stays in a metabolic chamber. It is used to measure metabolism.

The trial is Open with a status of Recruiting.

Investigator: Susi M Votruba, Ph.D.

Referral Contacts: (602) 200-5336

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Food Intake Response to Short-Term Modifications of Metabolism in Humans

One reason people gain weight is eating more calories from food than what they need for energy over 24 hours. Metabolism is the amount of energy a person uses over 24 hours. Researchers want to study the relationship between changes in metabolism and how much a person eats. Objectives: To see how much food a person eats when the body's temperature is cooled. To study how changes in metabolism may alter the amount of food a person eats. Eligibility: Healthy people ages 18-55. Design: Participants will stay at NIH for 20 days. During the first 4 days, participants will have: - Medical exam - Electrocardiogram - Blood and urine tests. One blood test includes drinking a sugar solution. - DXA body composition scan - Questions about foods they like, physical activity, and personal behavior - Exercise test on a stationary bicycle Participants will spend 24-hour periods in a metabolic chamber. The chamber will be at normal room temperature or cooler. Some times, participants will eat a diet that matches their daily needs. Other times, they can eat as much as they wish from a vending machine. Participants will have blood and urine collected. Participants will swallow an ingestible wireless sensor and wear a small data recorder device. On the second to last day, participants will stay in the metabolic chamber but only consume water and non-caffeinated sugar-free beverages. Participants will come back for 1-day visits at six months and one year from the first admission. They will have blood and urine tests, and a DXA scan. They will answer questions on physical activity and food habits.

The trial is Open with a status of Recruiting.

Investigator: Douglas Chang, M.D.

Referral Contacts: Not Listed

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Effects of Brain Stimulation on Food Intake and Behavioral Weight Loss Treatment

This study will determine whether electrical stimulation of an area of the brain called the dorsolateral prefrontal cortex, which is important in determining the feeling of fullness after eating, affects how much food a person eats and weight loss over 4 weeks. It will also compare weight changes in people who attend weight loss counseling sessions and those who do not over this period of time. Obese, non-diabetic people between 18 and 60 years of age who are in good health and who live in the Phoenix, AZ, metropolitan area are eligible for this study. Candidates must have a body mass index of 35 kg/m(2) or more and weigh less than 350 pounds. Participants are admitted to the NIH inpatient unit in Phoenix for the first 9 days of the study for tests, which include meal tests to determine eating behaviors and caloric intake, blood and urine tests, glucose tolerance test, weight measurement, psychological assessments and DEXA scan to measure body fat. For 3 of the days, they will be asked to eat all of their food from automated vending machines. Some subjects receive transcranial direct current stimulation (TDCS). For this procedure, electrodes that conduct electricity are placed on the head and arm and the current is turned on for 40 minutes. Some tingling may be felt under the electrodes. Other subjects receive sham TDCS, with the current turned on only very briefly. After the evaluations, subjects are discharged home from the NIH unit and instructed to eat 25 percent fewer calories than they consumed while on a weight maintenance diet the first 3 days of their inpatient stay. They maintain the lower calorie diet at home for 4 weeks. During this period they come to the NIH unit 3 days a week to receive either real or sham TDCS.

The trial is Open with a status of Recruiting.

Investigator: Marci E Gluck, Ph.D.

Referral Contacts: (602) 200-5300

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The Food Intake Phenotype: Assessing Eating Behavior and Food Preferences as Risk Factors for Obesity

The prevalence of obesity in the United States has reached alarming proportions with 33% of adults over the age of 20 being overweight. Obesity is more than twice as prevalent, however, in the Pima Indians of Arizona. Although there have been a number of advances in our understanding of the genetics of obesity, the environmental influences on the genetic expression of obesity requires further investigation. In an effort to understand some of the influences on the high prevalence of obesity in the Pima Indians, the present study was designed to investigate eating behaviors and food preferences, most especially the preference for high fat foods, in sib-pairs of Pima Indians who have been previously genotyped in our genomic scan for loci linked to diabetes/obesity. Most specifically, we will utilize several questionnaires and methods of assessing eating behavior and the preference for high fat foods to create a food intake phenotype. In addition, we will study Caucasians so that comparisons can be made between these two groups. We will make these evaluations by assessing eating behavior, food preferences including usual fat intake and preferences for high fat foods, body image perceptions, and energy expenditure. It is hoped that the data gathered from this study will elucidate some of the risk factors for the development of obesity among the Pima Indians....

The trial is Open with a status of Recruiting.

Investigator: Susi M Votruba, Ph.D.

Referral Contacts: (602) 200-5300

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Last Reviewed November 2023