Pistachio snacking to improve metabolic flexibility in adults with overweight
Official title: Effects of Pistachio Snacking on Metabolic Flexibility in Healthy Overweight and Obese Adults
Run by University of South Carolina · NCT07340125 · Data updated 2026-11-12
We will try eating pistachios for a few days to see if it helps adults with overweight or obesity use energy better at rest, during exercise, and after exercise.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 25 Years to 45 Years |
| Sex | All |
| Enrollment | 60 (estimated) |
| Sponsor | University of South Carolina Academic / other |
| Locations | 1 site (Columbia, South Carolina) |
| Status | Recruiting |
| Started | September 1, 2025 |
| Main results expected | August 1, 2026 |
| Study ends | December 31, 2026 |
| Registry record updated | January 14, 2026 |
| Trial ID | NCT07340125 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults aged 25–45 with BMI 25.0–34.9 kg/m², poor sleep quality (PSQI ≥ 5), otherwise healthy, not meeting weekly physical activity recommendations, and without tree nut allergies are ideal candidates.
✕Probably not a fit
People with tree nut allergies, diagnosed metabolic or cardiovascular conditions (for example diabetes or PCOS), those outside the specified BMI or age range, those already meeting exercise guidelines, or those following restrictive diets are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This randomized crossover study has participants complete four days of pistachio snacking and four days of their usual diet in random order. Primary outcomes are resting substrate metabolism, metabolic flexibility during exercise, and post-exercise substrate metabolism measured before and after each condition using indirect calorimetry. Secondary outcomes include changes in diet quality from diet logs, and exploratory outcomes include daily physical activity (steps, intensity), nightly sleep characteristics, daytime sleepiness, and hunger. Eligible participants are otherwise healthy adults aged 25–45 with BMI 25.0–34.9 kg/m² and poor sleep quality, and all testing occurs in person at a clinical exercise research center.
Why it matters
Potential benefit: If successful, short-term pistachio snacking could be a simple dietary change that modestly improves metabolic flexibility and potentially diet quality, sleep, or recovery after exercise.
How similar studies have gone: Previous research shows tree nut consumption can improve diet quality and some cardiometabolic markers, but using short-term pistachio snacking specifically to change metabolic flexibility is relatively novel and not well established.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Males and Females * Age: 25-45 years * Overweight or obese (BMI=25.0-34.9 kg/m²) * Poor sleep quality (Pittsburgh Sleep Quality Index ≥ 5) * Healthy (no diagnosed metabolic, cardiovascular, sleep, or other health condition that may significantly alter metabolism, sleep, or ability to participate in the exercise test) * Not meeting weekly physical activity recommendations (\<150 min moderate-intensity exercise, \<75 minutes of vigorous-intensity exercise, and \<2 days of strength training) * Not following a diet that is restrictive or eliminates certain food group/types Exclusion Criteria: * Allergies to nuts, especially tree nuts * Has a pacemaker * Following a diet that is restrictive or eliminates certain food group/types * Self-repoted health or disease state that may influence study outcomes, including known metabolic or endocrine disorder (e.g. prediabetes, type 1 or type 2 diabetes, or polycystic ovary syndrome), cardiovascular diseases, neuromuscular disorders, musculoskeletal disorders; current or recent history of cancer/cancer treatment (within the past year) * History of gastrointestinal surgery, hysterectomy * For women: pregnant or thinking of becoming pregnant during the time of participation, pregnant within the last year, currently breastfeeding, or known to be perimenopausal
Where it's running
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Public Health Research Center: Clinical Exercise Research Center
Columbia, South Carolina, United States Recruiting
Study contacts
- Principal investigator: Katie R Hirsch, PhD — University of South Carolina
- Study coordinator: Callie Unrein, MS
- Email: sustainlab@mailbox.sc.edu
- Phone: 803-777-5478
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.