NCT07853898 · St. Louis University
Effects of Pistachios on Postprandial Metabolic Responses in Adults With Overweight or Obesity
What this study is about
This randomly assigned controlled crossover study will examine the acute effects of pistachio consumption on postprandial metabolic responses in adults with overweight or obesity. Participants will complete two experimental conditions in randomly assigned order.
View original scientific description
This randomized controlled crossover study will examine the acute effects of pistachio consumption on postprandial metabolic responses in adults with overweight or obesity. Participants will complete two experimental conditions in randomized order. In one condition, participants will consume 30 g of pistachios with a standardized meal, and in the other condition they will receive an isocaloric refined-carbohydrate control condition with the standardized meal. The study will evaluate postprandial insulin and glucose responses over approximately 3 hours after meal consumption. Additional outcomes will include continuous glucose monitoring measures, blood lipid responses, appetite and satiety ratings, and exploratory measures related to insulin sensitivity and gastrointestinal hormone responses. The study is designed to determine whether pistachio consumption alters acute metabolic responses compared with an isocaloric refined-carbohydrate control in adults with overweight or obesity.
Interventions
OTHER
Pistachio Co-consumption
Participants will consume 30 g of shelled, lightly salted pistachios together with a standardized high-glycemic breakfast meal. The pistachios and standardized breakfast meal will be consumed within a fixed 10-minute meal period.
OTHER
Refined-Carbohydrate Control Co-consumption
Participants will consume an isocaloric refined-carbohydrate control food together with the same standardized high-glycemic breakfast meal. The control food will be matched to the pistachio condition for energy content as closely as possible while providing minimal fiber, protein, unsaturated fat, and bioactive compounds.
Primary outcome measures
Postprandial Insulin Incremental Area Under the Curve (iAUC)
Time frame: 0-180 minutes after meal consumption
Postprandial plasma insulin will be measured at 0, 30, 60, 90, 120, 150, and 180 minutes after meal consumption. Insulin incremental area under the curve (iAUC) from 0 to 180 minutes will be calculated using the trapezoidal rule with baseline subtraction. Insulin iAUC will be compared between the pistachio and refined-carbohydrate control conditions.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age 18-35 years, male or female, and able to provide informed consent.
- BMI ≥25.0 kg/m². Waist circumference and BIA-derived body composition will also be assessed during screening and considered with BMI to help confirm that elevated BMI reflects excess adiposity rather than primarily high muscularity.
- Weight stable, defined as no intentional weight loss or body weight change \>3 kg during the previous 3 months.
- Generally healthy and not currently taking medications known to substantially affect glucose metabolism, insulin secretion, insulin sensitivity, appetite, or body weight. Stable thyroid hormone replacement for a well-controlled thyroid condition is not automatically
Exclusion criteria
- Able to complete a 10-12-hour overnight fast and refrain from vigorous exercise and alcohol for 24 hours before each test meal visit.
- Able and willing to consume pistachios, the refined-carbohydrate control food, and the standardized breakfast meal. Exclusion Criteria:
- Known diagnosis of type 1 or type 2 diabetes. Individuals with known prediabetes will not be excluded.
- Clinically significant cardiovascular disease, including prior myocardial infarction or stroke, uncontrolled hypertension, clinically significant arrhythmia, or another cardiovascular condition that could make participation unsafe or meaningfully affect study outcomes.
- Chronic kidney disease or another major medical condition that could make participation unsafe or meaningfully affect metabolic outcomes.
- Current participation in a weight-loss program, use of weight-loss medications, or history of bariatric surgery within the past year.
- Known allergy or intolerance to pistachios, tree nuts, peanuts/peanut butter, wheat/gluten, orange juice/citrus, or any other study-meal ingredient.
- Celiac disease, Crohn's disease, ulcerative colitis, or another clinically significant gastrointestinal or malabsorption condition that could affect digestion, nutrient absorption, or metabolic responses.
- Current ketogenic, very-low-carbohydrate, or medically prescribed diet that could meaningfully interfere with the standardized feeding protocol or metabolic outcomes.
- Participation in another clinical research trial within the past 3 months that could affect participant safety or study outcomes.
- Recent significant illness, infection, or surgery within the past 4 weeks that could affect participant safety or study outcomes.
- Current or prior clinically significant eating disorder that, in the investigator's judgment, could make participation unsafe or interfere with the feeding protocol.
- Current smoking, frequent nicotine use, or excessive alcohol use.
- Pregnancy, planned pregnancy during the study period, or lactation.
- Any condition or medication that, in the investigator's judgment, would make participation unsafe or interfere with outcome measures.
Where
- St Louis, Missouri
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Oct 2, 2026 · Source of record for eligibility and locations