An interventional study of Diet A and Diet B in Nutrition, Health and Dietary Habits, sponsored by RTI International. Recruiting at 14 sites in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-13.
Sponsored by RTI International · Not applicable, Interventional, and Other
The goal of this Nutrition for Precision Health (NPH) powered by All of Us research study is to develop Artificial Intelligence/Machine Learning (AI/ML) algorithms that predict individual responses to diet patterns using rich multimodal data streams collected across multiple domains (e.g., behavior, social, environmental, clinical and molecular biomarkers). NPH includes a large phenotyping cohort (Module 1, N=8000) and two separate follow-up groups drawn from a subset of Module 1participants. One group (Module 2, N=1200) receives three distinct diets in a 14-day crossover sequence, with at least a 14-day washout period between diets, while living in their own homes. A second group (Module 3, N=150) receives the same three diets under full-time supervision in a residential research setting. We will train and test AI/ML models to predict 0-4 hour postprandial response curves for glucose, insulin, triglycerides, and GLP-1, to the standardized diet-specific meal test (DSMT) collected after each of the three different diets delivered in Module 2. Each diet functions as a controlled stimulus to reveal biological features (such as individual variables, patterns, or clusters of measurements) that best predict a person's response.
The Module 2 DSMT response curves are the primary outcomes (dependent variables) for AI/ML algorithms that predict individual responses to diet patterns.
As a secondary objective, NPH will evaluate the validity and acceptability of technology-based dietary assessment tools. The Automated Self-Administered 24-hour recall (ASA24), Automatic Ingestion Monitor-2 (AIM-2), and the mobile food record (mFR) will be evaluated in Modules 2 and 3, and the ASA24 food record and the image-assisted ASA24 recall will be evaluated only in Module 3. Total energy intake, macronutrient and dietary fiber intake data are the main outcomes for validity testing compared against measures of actual intake. Acceptability will be determined from feedback surveys.
The Nutrition for Precision Health (NPH) study is a multi-module, large-scale project with observational and interventional components embedded in the All of Us Research Program. The overarching goal is to develop artificial intelligence and machine learning (AI/ML) algorithms that predict individual responses to different diet patterns. The study consists of three modules designed to balance breadth (large scale phenotyping) and depth (controlled dietary interventions):
Module 1: Phenotyping (non-interventional)
Module 2: Community-dwelling controlled feeding group (Intervention arm 1)
Module 3: Residential (Live-in) controlled feeding group (Intervention arm 2)
Approximately 8,000 participants are anticipated to be enrolled in Module 1. From this cohort, approximately 1,200 participants will enroll in Module 2, and a separate subset of Module 1 participants (approximately 150 participants) will enroll in Module 3. Module 1 is observational and only Modules 2 and 3 are interventional in nature (intervention arms).
Module 1 is a phenotyping observational study. Participants undergo comprehensive characterization across an 8 to 10-day baseline period for assessments including: clinical measures, biospecimen collection, wearable sensor monitoring, questionnaires, and a liquid meal test (LMT). During the LMT, participants ingest a standardized liquid meal with a dose of acetaminophen for estimating gastric emptying and provide timed blood samples for postprandial profiling. The LMT is a diagnostic stimulus used solely for feature generation and is not being evaluated as an intervention. The resulting Module 1 high dimensional dataset supports machine learning methods (e.g., PCA, clustering, recursive feature elimination) for candidate predictor discovery and is therefore not listed in the Arms/Interventions section. Module 1 data will be used to develop novel statistical and machine learning methods to learn individual and generalizable causal models of nutrition and health, particularly in the presence of missing or incomplete data. The scale of Module 1 enables discovery of causal pathways and moderators between physical and contextual measures, LMT responses, and continuous glucose monitoring (CGM) data. These insights are critical for developing models that not only predict individual dietary responses but also explain why and under what conditions they occur.
Module 2 is a community dwelling controlled feeding arm (Intervention arm 1). A subset of Module 1 participants will enroll in Module 2, in which participants consume three standardized eucaloric diets; Diet A, Diet B, Diet C, in a crossover sequence. Each diet period lasts 12-14 days, separated by a minimum of 14-day washout period between diets. All meals are provided, but participants remain in their community dwelling environments. Participants undergo one of six possible sequences of dietary interventions, reflecting all possible orderings of the three diets (ABC, ACB, BCA, BAC, CAB, and CBA). To reduce potential bias, all six diet sequences are included in the crossover design. Rather than assigning diet sequences to individual participants, a cohort-based randomization approach is used to reduce operational burden on the metabolic kitchens. In this approach, pre-generated schedules involving all 6 diet sequences are randomly assigned to the clinical site metabolic kitchens, with each diet sequence corresponding to a cohort. Participants are then enrolled into the cohorts. The six diet orders are repeated over time at each site until the full enrollment targets for Modules 2 and 3 are met. Each site follows a different randomized version of the overall cohort schedule, which ensures distribution of the possible diet orders across time and clinical sites while preserving balance and logistical feasibility. Wearable-generated data (like accelerometry and CGM), physical and contextual measures are collected throughout.
At the completion of each diet participants are provided a standardized breakfast meal test, DSMT, from each of the three provided diets (Diet A, B, C). The 0-4 hour postprandial response curves are then used to evaluate inter-individual variation and unmask features collected in Module 1 and 2 that contribute to the AI/ML predictions of the response.
Each breakfast serves as a controlled stimulus to reveal underlying biological features from rich multimodal data streams, including clinical, molecular, behavioral, environmental, and social domains that may drive interindividual variability in metabolic response. For each DSMT, participants provide blood samples for up to nine time points over four hours. Analyte concentrations of glucose, insulin, triglycerides, and GLP-1, are used to construct response curves. The primary outcomes are the area under the curve (AUC) for each analyte (glucose, insulin, triglycerides, GLP-1) following each DSMT. This approach parallels a cardiac stress test: the stimulus (the meal) is a probe to expose individual variability in physiological function. Module 2 data will also be used to develop novel statistical and machine learning methods that produce individual and generalizable causal models of nutrition and health.
Module 3 is a controlled feeding study (Intervention arm 2) that is implemented in the live-in/residential setting. A separate subset of Module 1 participants completes the same three diets (Diet A, B, C) as in Module 2, but while residing in a research setting with full supervision of intake, activity, and sleep. The same cohort randomization scheme as in Module 2 determines diet order. The residential environment in Module 3 provides the highest degree of experimental control, allowing isolation of physiological effects of diet composition. Participants undergo a diet-specific meal test (DSMT) as well as a liquid meal test (LMT) accompanied by a dose of acetaminophen after completing each of the diets. In addition, intake balance studies are conducted in this module using the doubly labeled water assessments and DXA for body composition. Data from Module 3 will help quantify and separate variance in the AI/ML models attributable to adherence and other community dwelling factors observed in Module 2 and enables rigorous and controlled comparison against causal relationships discovered in Module 2 data.
In both Modules 2 and 3, participants are masked to the nutritional profile of each diet to minimize expectancy bias. Investigators and diet implementation staff are unmasked.
985 studies on the registry are indexed under Feeding Behavior; 178 are open to participants now.
This study's planned enrollment of 8,000 is above the median of 77 across 700 interventional studies indexed under Feeding Behavior.
Browse Feeding Behavior studies →RTI International is the lead sponsor of 84 studies on the registry; 18 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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.
Exclusion Criteria:
Module 1
Barriers to safe insertion of peripheral IV canula:
Pregnancy-related conditions:
Certain types of disease states:
Swallowing issues:
Module 2
Pregnancy-related conditions:
History of surgery for the treatment of obesity and:
Uncontrolled disease states:
Module 3
Depression as assessed by:
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.
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.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
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.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants drawn from Module 1 will receive three standardized diets (A, B, and C) in one of six sequences. Diet sequences are assigned at the cohort level based on a pre-defined site-specific schedule. All meals are provided while participants remain living in their own homes. Each diet period lasts \~14 days, separated by washouts of at least 14 days. Participants are masked to the nutritional content of each diet. Data collection includes wearable device outputs, physical and contextual assessments, and biospecimens. This arm evaluates metabolic responses to controlled diets under real-world, community-dwelling conditions.
Other: Diet A · Other: Diet B · Other: Diet C
A separate group of participants drawn from Module 1, who are not enrolled in Module 2, will receive the same three standardized diets administered in Module 2 while residing in a fully supervised residential setting. Diet sequences are assigned at the cohort level based on a pre-defined site-specific schedule. Each diet period will last approximately 14 days and will be separated by washout periods of at least 14 days. Intake, activity, and sleep will be closely monitored. Participants will also complete the same liquid meal test administered in Module 1 (see detailed description) after each of the diet periods. A wealth of measurements will be collected, including data from wearables, physical and contextual measures, and biospecimens. Intake balance studies are conducted in this module using the doubly labeled water assessments and DXA for body composition. Module 3 is designed to isolate the response to different diets from behavioral variability observed in community settings.
Other: Diet A · Other: Diet B · Other: Diet C
This diet has high amounts of fruits/vegetables, whole grains, and beans, moderate amounts of dairy, meat/poultry/eggs, nuts/seeds, and olive oil, and very low amounts of sugar sweetened drinks and desserts.
This diet has high amounts of refined grains, meat/poultry/egg, sugar sweetened drinks, snacks, desserts, and processed foods. It has a moderate amount of dairy and low amounts of fruits/vegetables, whole grains, and fish.
This diet has moderate-high amounts of vegetables, meat/poultry/egg, nuts/seeds, dairy and fats/oils, low amounts of fruits, and very low amounts of grains and sugars.
Glucose - Diet Specific mixed meal tolerance test (MMTT) Diet A
Area under the curve (AUC) for glucose measured during the diet-specific MMTT for Diet A.
Time frame: 4 hours
Insulin - Diet Specific mixed meal tolerance test (MMTT) Diet A
Area under the curve (AUC) for insulin measured during the diet-specific MMTT for Diet A.
Time frame: 4 hours
Triglycerides - Diet Specific mixed meal tolerance test (MMTT) Diet A
Area under the curve (AUC) for triglycerides measured during the diet-specific MMTT for Diet A.
Time frame: 4 hours
GLP-1 - Diet Specific mixed meal tolerance test (MMTT) Diet A
Area under the curve (AUC) for Glucagon-Like Peptide-1 (GLP-1) measured during the diet-specific MMTT for Diet A.
Time frame: 4 hours
Glucose - Diet Specific mixed meal tolerance test (MMTT) Diet B
Area under the curve (AUC) for glucose measured during the diet-specific MMTT for Diet B.
Time frame: 4 hours
Insulin - Diet Specific mixed meal tolerance test (MMTT) Diet B
Area under the curve (AUC) for insulin measured during the diet-specific MMTT for Diet B.
Time frame: 4 hours
Triglycerides - Diet Specific mixed meal tolerance test (MMTT) Diet B
Area under the curve (AUC) for triglycerides measured during the diet-specific MMTT for Diet B.
Time frame: 4 hours
GLP-1 - Diet Specific mixed meal tolerance test (MMTT) Diet B
Area under the curve (AUC) for Glucagon-Like Peptide-1 (GLP-1) measured during the diet-specific MMTT for Diet B.
Time frame: 4 hours
Glucose - Diet Specific mixed meal tolerance test (MMTT) Diet C
Area under the curve (AUC) for glucose measured during the diet-specific MMTT for Diet C.
Time frame: 4 hours
Insulin - Diet Specific mixed meal tolerance test (MMTT) Diet C
Area under the curve (AUC) for insulin measured during the diet-specific MMTT for Diet C.
Time frame: 4 hours
Triglycerides - Diet Specific mixed meal tolerance test (MMTT) Diet C
Area under the curve (AUC) for triglycerides measured during the diet-specific MMTT for Diet C.
Time frame: 4 hours
GLP-1 - Diet Specific mixed meal tolerance test (MMTT) Diet C
Area under the curve (AUC) for Glucagon-Like Peptide-1 (GLP-1) measured during the diet-specific MMTT for Diet C.
Time frame: 4 hours
Accuracy of energy intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to known intake from objective measures.
Agreement will be assessed between total daily energy intake in kilocalories reported via each dietary assessment tool and known intake from the intake-balance method using doubly labelled water and provided diets.
Time frame: 14 days
Accuracy of energy intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to measured intake from provided diets.
Agreement between energy reported via each dietary assessment tool and measured intake from provided diets, in grams per day.
Time frame: 14 days
Accuracy of carbohydrate intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to measured intake from provided diets.
Agreement between carbohydrate intake reported via dietary assessment tool and measured intake from provided diets, in grams per day.
Time frame: 14 days
Accuracy of protein intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to measured intake from provided diets.
Agreement between protein intake reported via each dietary assessment tool and measured intake from provided diets, in grams per day.
Time frame: 14 days
Accuracy of fat intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to measured intake from provided diets.
Agreement between fat intake reported via each dietary assessment tool and measured intake from provided diets, in grams per day.
Time frame: 14 days
Accuracy of dietary fiber intake estimates from tool (ASA24, mFR, AIM-2, ASA24 record, mFR+ASA24) compared to measured intake from provided diets.
Agreement between dietary fiber intake reported via each dietary assessment tool and measured intake from provided diets, in grams per day.
Time frame: 14 days
Acceptability scales for ASA24 and Diet A
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for ASA24 and Diet B
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for ASA24 and Diet C
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR and Diet A
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR and Diet B
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR and Diet C
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for AIM-2 and Diet A
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for AIM-2 and Diet B
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for AIM-2 and Diet C
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for ASA24 Record and Diet A
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for ASA24 Record and Diet B
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for ASA24 Record and Diet C
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR+ASA24 and Diet A
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR+ASA24 and Diet B
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Acceptability scales for mFR+ASA24 and Diet C
Responses to questions on ease of use and tool preference. Principal outcomes will be "ease of use" and "willingness to use again."
Time frame: 14 days
Not enrolling at this site.
Plan to share: Yes — IPD and related data dictionaries will be available in the All of Us Researcher Workbench.
Supporting information: Study protocol
Time frame: One year after study completion
Access criteria: Per the policies of the All of Us Research Workbench
Data sharing details ↗ · researchallofus.org
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 ↗
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