Recruiting

Pistachio Consumption

Sponsor:

St. Louis University

Code:

NCT07853898

Conditions

Obesity / Overweight

Eligibility Criteria

Sex: All

Age: 18 - 35

Healthy Volunteers: Not accepted

Interventions

Pistachio Co-consumption

Refined-Carbohydrate Control Co-consumption

Study Details

Brief summary:

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.

Conditions

Obesity / Overweight

Study ID

NCT07853898

Start date

Oct, 2026

Status verified date

Sep, 2026

Completion date

Jul, 2027

Anticipated

Primary completion date

Jul, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 35

Healthy Volunteers: Not accepted

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 exclusionary.
  • 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.

Study Design

Enrollment

28 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Pistachio Then Control Sequence

Participants randomized to this sequence will first complete the pistachio condition, in which 30 g of shelled pistachios are consumed with the standardized high-glycemic breakfast meal. After a 3-7 day washout period, participants will complete the refined-carbohydrate control condition, in which an isocaloric refined-carbohydrate control food is consumed with the same standardized breakfast meal.

experimental: Control Then Pistachio Sequence

Participants randomized to this sequence will first complete the refined-carbohydrate control condition, in which an isocaloric refined-carbohydrate control food is consumed with the standardized high-glycemic breakfast meal. After a 3-7 day washout period, participants will complete the pistachio condition, in which 30 g of shelled pistachios are consumed with the same standardized breakfast meal.

Interventions

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.

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 measure

  • Postprandial Insulin Incremental Area Under the Curve (iAUC) [ Time Frame: 0-180 minutes after meal consumption ]

Central Contacts and Locations

Central contacts

Hossein Rafiei, PhD, RD

314-977-8675hossein.rafiei@health.slu.edu

Locations

Saint Louis University

Recruiting

St Louis, Missouri, United States, 63104

Contacts

Hossein Rafiei, PhD RD

314-977-8675hossein.rafiei@health.slu.edu

Principal Investigator:

Hossein Rafiei, PhD, RD

More Information

Sponsor

St. Louis University

Last update posted

Oct 2, 2026

Last verified

Sep, 2026

Keywords

  • Pistachios
  • Postprandial glucose
  • Postprandial insulin
  • Metabolic response
  • Insulin sensitivity
  • Continuous glucose monitoring
  • Appetite

Trial information was received from ClinicalTrials.gov and was last updated on 2026-10-03. This information was provided to ClinicalTrials.gov by St. Louis University on 2026-10-02. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.