An interventional study of Standard Diet and Ketogenic Diet in Overweight and Obesity, 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 65 Years. Per ClinicalTrials.gov, last updated 2026-09-18.
Sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Not applicable, Interventional, and Basic science
Among 104 studies in Obesity by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) — 12 open to participants now, 13 under way, none of them phase 3. Obesity · National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Among the 104 studies in Obesity by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), this one is the 29th largest by planned enrollment of the 66 interventional ones that give a count, is one of 4 that started in 2024, is one of 40 with no phase, reaches primary completion later than 0 of the 10 other live ones, and was the 98th registered.
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
Browse Obesity studies →12 of the 104 studies in Obesity by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) are open now, in 1 country. Recruiting first, the newest first:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Sites in United States
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Sites in United States
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Sites in United States
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Sites in United States
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Sites in United States
By country, each count listing its studies:
Of the 1,336 Obesity studies recruiting now, 377 (28%) set no upper age limit and 856 (64%) stop at 75 or younger; 168 take children under 18; 491 take healthy volunteers.
This study: 18 Years to 65 Years · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
104 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 6 · Phase 2 22 · Phase 3 6 · Phase 4 1
First in 1983; this study’s year is marked. 4 started in 2024.
This study's planned enrollment of 100 is above the median of 67 across 9,006 interventional studies indexed under Obesity.
Median enrollment 100 across the 66 interventional studies, 144 across the 31 observational. Of the 88 that completed or were terminated, 10 (11%) have results posted.
This tab as a report to print or save as PDF → With an account.
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.
5 of the studies in Obesity by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06690294National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Assessing the Impact of Perceptions of Unpredictability on Objective Measures of Food Consumption and Metabolism | 2027-01-30 |
| NCT00739362National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Effects of Brain Stimulation on Food Intake and Behavioral Weight Loss Treatment | 2027-01-31 |
| NCT06044935National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Effect of Nicotinamide Riboside on Ketosis, Fat Oxidation & Metabolic Rate | 2027-01-31 |
| NCT05545306National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)The Effects of Increasing Caloric Intake on Diet-Induced Thermogenesis and 24h Energy Expenditure | 2027-02-02 |
| NCT06223555National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Variability In Mixed Meal Tests: Fixed Versus Adjusted to Energy Needs Caloric Dose | 2027-06-30 |
Among the 104 studies in Obesity by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), from their registry updates:
This tab as a report to print or save as PDF → With an account.
Background:
At least 30% of Americans have fatty liver disease. This means that they store too much fat in the liver. At the moment lifestyle changes are the only way to treat this problem.
Objective:
To test how (1) a low-carbohydrate diet and (2) a supplement called nicotinamide riboside (NR) affect how a person s body uses dietary fat.
Eligibility:
Men aged 18 to 65 and women aged 18 to 50 who are healthy volunteers with a body mass index (height to weight ratio) of 25 or more. Adults with maturity-onset diabetes of the young type 2 (MODY2) are also needed.
Design:
Participants with diabetes will have 1 screening visit and a 9-day clinic stay. Healthy volunteers will have 1 screening visit and 2 clinic stays of 1 to 2 weeks each.
During screening, all participants will have a physical exam with blood and urine tests. They will have their heart rhythm measured while riding a gym bike.
NR is a pill taken by mouth. Only healthy volunteers will take the NR, for 14 days at a time, during 1 clinic stay. During their other stay, they will take placebos; these are pills that look like the study supplement but contain no NR.
During each clinic stay, all participants will eat a normal American diet. Then they will eat a ketogenic "low-carb" diet for 5 days.
Participants will have many tests, including:
Sleeping every night and having two 24-hour stays in a special room that measures the gases their body uses and produces.
Drinking a high-fat shake, then remaining seated for 5 hours while their blood and breath are monitored.
Having a substance injected into the arm and remaining seated for 3 hours while their blood is measured.
Wearing monitors to measure their activity levels. Another monitor will measure their blood glucose levels.
Having imaging scans.
...
Study Description:
This is a randomized, double-blind, placebo-controlled crossover study of adults with overweight or obesity to determine whether nicotinamide riboside supplementation increases sleeping energy expenditure and fat oxidation rate during a ketogenic diet.
Objectives:
Primary Aim 1: Determine whether sleeping energy expenditure increases after transitioning to a low carbohydrate ketogenic diet as compared to a baseline high carbohydrate run-in diet in men
Primary Aim 2: Determine whether sleeping energy expenditure is affected by NR supplementation during a ketogenic diet in men
Secondary Aim 1: Determine whether fat oxidation during sleep increases after transitioning to a low carbohydrate ketogenic diet as compared to a baseline high carbohydrate run-in diet in men
Secondary Aim 2: Determine whether fat oxidation during sleep is affected by NR supplementation during a ketogenic diet from the baseline run-in diet in men
Exploratory Aims: Exploratory comparison of the above endpoints between men and women without MODY2.
Exploratory comparison of the above diet-related endpoints between patients with MODY2 and those obtained during the Placebo period in other participants.
Several exploratory measurements are planned to help comprehensively phenotype the effects of the diets and nicotinamide riboside supplementation and are intended to be hypothesis-generating. We will assess the following:
Endpoints:
Primary:
Mean change in sleeping energy expenditure between the ketogenic diet and the baseline run-in diet
Mean difference in sleeping energy expenditure between NR and placebo during the ketogenic diet
Secondary:
Mean change in sleeping fat oxidation rate between the ketogenic diet and the baseline run-in diet Mean difference in fat oxidation rate between NR and placebo during the ketogenic diet
Exploratory:
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
This study's planned enrollment of 100 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.
Compared within Obesity, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Overweight. The counts are of registry records indexed under each term, refreshed daily. How we classify →
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:
Meet one of the following:
EXCLUSION CRITERIA:
An individual who meets any of the following criteria will be excluded from participation in this study:
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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
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.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
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.
To investigate whether NR supplementation augments the sleeping energy expenditure and fat oxidation rate during the ketogenic diet in men and women with overweight and obesity
Other: Standard Diet · Other: Ketogenic Diet · Dietary Supplement: Placebo · Dietary Supplement: Nicotinamide Riboside
To measure changes in sleeping energy expenditure and fat oxidation rate after transitioning from a baseline diet to an isocaloric ketogenic diet similar to our previous study in men
Other: Standard Diet · Other: Ketogenic Diet · Dietary Supplement: Placebo
To investigate whether NR supplementation augments the sleeping energy expenditure and fat oxidation rate during the ketogenic diet in men and women with overweight and obesity
Other: Standard Diet · Other: Ketogenic Diet · Dietary Supplement: Placebo · Dietary Supplement: Nicotinamide Riboside
Consisting of 15% protein, 35% fat, and 50% carbohydrate, matching the macronutrient composition of a typical American diet
Consisting of a macronutrient composition of 15% protein, 80% fat, and 5% carbohydrate
Subjects without MODY2 will take either placebo or NR (1 g BID, 2 g per day total) supplements for 7 days during this Run-in phase
Subjects without MODY2 will take either placebo or NR (1 g BID, 2 g per day total) supplements for 7 days during this Run-in phase
Mean change in sleeping energy expenditure between the ketogenic diet and the baseline run-in diet
Mean change in sleeping energy expenditure measured by room calorimetry from 2 days of standard run-in diet to 5 days of ketogenic diet
Time frame: 7 days
Mean difference in sleeping energy expenditure between NR and placebo during the ketogenic diet
Mean difference in sleeping energy expenditure measured by room calorimetry during 5 days of ketogenic diet with NR supplementation or placebo
Time frame: 5 days
Mean change in sleeping fat oxidation rate between the ketogenic diet and the baseline run-in diet
Mean change in sleeping fat oxidation measured by room calorimetry from 2 days of standard run-in diet to 5 days of ketogenic diet
Time frame: 7 days
Mean difference in fat oxidation rate between NR and placebo during the ketogenic diet
Mean difference in sleeping fat oxidation measured by room calorimetry during 5 days of ketogenic diet with NR supplementation or placebo
Time frame: 5 days
Plan to share: Yes — demographics, anthropometrics, indirect calorimetry data, circulating metabolites and hormones
Supporting information: Study protocol, Analytic code
Time frame: Upon publication in peer reviewed journal
Access criteria: Open
Started Jan 2024 (actual). Primary completion is estimated for Jan 2027, 36 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 36 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.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Studies of the drug tested here: Nicotinamide-beta-riboside
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) →