Food and Metabolism Study (FAM)

Effects of Avocado on Triglyceride Metabolism in Individuals With Insulin Resistance

In this study, we are interested in looking at the influence of eating avocados regularly, which are rich in healthy fats, fibers, and unique carbohydrates, on triglyceride and glucose metabolism in people with prediabetes and insulin resistance.

Study Overview

• Status: Not yet recruiting
• Conditions: Insulin Resistance; Prediabetes; Triglycerides; Lipids Metabolism
• Intervention / Treatment: Other: Avocado meal plan; Other: Control meal plan

Detailed Description

The proposed study will be conducted in humans according to Good Clinical Practice (GCP) guidelines. All subjects will review and sign an Informed Consent Form approved by the Illinois Institute of Technology's Institutional Review Boards (IRB) prior to screening. The research is designed as a randomized, 2-arm, parallel, diet-controlled, human clinical trial to investigate the effects of avocado consumption for 4 weeks on triglyceride metabolism in individuals with insulin resistance.

Participants will be asked to do the items described below. Visits will be held at the Clinical Nutrition Research Center (CNRC) on the IIT Campus, 10 W. 35th St., Suite 3D6-1 Chicago, IL, 60616.

SCREENING VISIT

Eligibility for the study is based on the above list (inclusion and exclusion criteria). We will determine if participants qualify for the study at the Screening Visit by the following measurements:

• General measurements: height, weight, body composition and body temperature
• Fasting blood glucose (sugar) from a finger prick
• Venous blood collection to assess blood glucose, insulin, and triglycerides
• Pregnancy test, for women under the age of 60

Demographic questionnaire, health and medication questionnaire: participants will be asked to provide personal information, such as their name, date of birth, race, etc. We will also ask them to answer questions about their demographics, health, medical history, and the medications they are taking. Based on the results of the blood draw, questionnaires, measurements, and evaluation of their health, they may meet the criteria and be invited to participate in the study.

PRE-STUDY / PRE-INTERVENTION VISIT (which may be performed on the same or a different day as the screening visit) The Pre-Study visit lasts ~45 minutes to 1 hour and participants will meet with one of our investigators who will provide detailed instructions on procedures of the study and "how to prepare for each of your study days." They will be trained in all study procedures, including, but not limited to, foods to avoid during the study, medications/supplements to avoid, food diary recording, gastrointestinal diary recording and fasting overnight. Their study dates will be scheduled, and they will be provided with a study booklet, including a study calendar and all instructions covered at the Pre-Study Visit.

Medications/Supplements: If they are taking any medications or supplements that do not interfere with the study or have been OK'd by study staff, they will take those as instructed by their doctor and will record them in their diary. We will train the participants on what foods or supplements are OK and NOT OK during the study at the Pre-Study Visit.

Self-Characteristics and Dietary Surveys: Participants will be asked to complete online surveys that cover usual gastrointestinal symptoms and a 24-hour food recall (ASA24).

STUDY DAY VISITS Study Visit 1 / Day 0 and Visit 5 / Day 28 Procedures

Staff collects study materials from the participant

1. Diary and provide 24 h recall (ASA24) Confirmation participant is ready to go for their study day by interview/discussion with the study staff

1. Fasted overnight for 10-12 hours, including finger prick to verify usual fasting glucose
2. Had a usual night of sleep (5-6 hours minimum)
3. Avoided alcohol and vigorous physical activity 24 hours before the study day

After confirming they are ready for their study day, we will proceed to an exam room to measure:

Anthropometrics: We will measure weight and body composition. Vital signs: We will check their blood pressure, heart rate, and body temperature using standard clinic devices.

Once we've collected measurements, we will proceed with an IV catheter to collect blood over multiple timepoints.

Blood collection: Participants will see the Licensed Health Care Provider (LHCP) for blood sample collection. We will use an indwelling catheter (IV). This means we will use a needle to put a thin tube in their arm or hand, from which we can get blood samples while keeping them as comfortable as possible. This tube will stay in their arm until all blood drawings are completed during their visit. If there is difficulty with blood flow we will ask the participant if they're comfortable with single stick blood collection, performed by LHCP using a butterfly needle. There will be nine blood draws in total over 5 hours.

Once the fasting blood draw is collected, we will provide the participant with a breakfast in the form of a nutritionally complete liquid meal test (LMT).

Standard Liquid Meal Test (LMT): For this test, they will drink about 2 cups of vanilla flavored Ensure®. Ensure® is a nutritional supplement containing a mixture of sugars, fats, and protein and a variety of vitamins and minerals. The drink contains milk protein (suitable for lactose intolerance) and soy products. We will ask if they are unwilling to consume any ingredients in the Ensure® drink. It may be unsafe for them to complete this test if they have an allergy to any of the components. The total amount you will drink will be approximately 440 calories, 64g of Carbs, 12g of Fat, and 18g of Protein.

After all blood samples have been collected they will be provided with meals to last until V2 (~ 1 week) and instructed how to fill out the dietary adherence log.

MEAL PICKUP VISITS Study Visit 2 / Day 7, Study Visit 3 / Day 14, Study Visit 4 / Day 21

Participants will not need to come fasted for meal pickup visits. We will collect materials and ensure they are complying with the study protocols, and assess if there are any difficulties we can help with. The following will be done at pickup visits:

Staff collects study materials from the participant 1. Diary and provide 24 h recall (ASA24) Staff collects weight and LDN does counseling as needed

1. Licensed Dietitian Nutritionist (LDN) will review compliance diary and weight changes and provide nutrition counseling as needed

• Study Type: Interventional
• Enrollment (Estimated): 82
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Chelsea Preiss, MS; Phone Number: 312-567-5300; Email: cpreiss@illinoistech.edu
• Study Contact Backup: Name: Indika Edirisinghe, PhD; Phone Number: 708-563-8178; Email: iedirisi@illinoistech.edu

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60616
      • Clinical Nutrition Research Center at IIT

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Men or women, 40-70 years of age.
• Fasting triglycerides (TG) >115 mg/dL.
• Insulin resistance as measured by HOMA-IR >2.5.
• Able to provide informed consent.
• Able to comply with and perform the procedures requested by the protocol, specifically eat all the meals and snacks provided by the study which will be almost all your food (~ 80% of calories per day).
• Able to come to the clinic up to 6 times during the study.
• Able to maintain usual physical activity pattern.
• Able to avoid/abstain from alcohol and vigorous physical activity for 24 hours prior to and during study visit.

Exclusion Criteria:

• Men and women with known or suspected intolerance, allergies or hypersensitivity to study foods or interventions.
• Fasting blood sugar ≥125 mg/dL. Men and women with blood pressure >160 mmHg (systolic) / 100 mmHg (diastolic) at the screening visit.
• Men and women with history of diabetes cardiovascular events, respiratory, renal, gastrointestinal, hepatic or eye disease or surgery- within a year.
• Men and women who have or had cancer other than non-melanoma skin cancer in the past 5 years.
• Men and women taking over the counter or prescription medications or dietary supplements that may interfere with study procedures or endpoints.
• Men and women who are on a specialized diet (vegan, vegetarian, keto, etc.). - - Men and women who consume nuts or peanuts daily or most days of the week.
• Men and women who are not weight stable (+/-10lbs in previous 2 months). Men and women who have excessive use of drugs or alcohol (ie., addictions) within the past 2 years.
• Men and women with documented physical or mental disease/condition, which might limit participation in or completion of the study or, that, in the opinion of the investigator, could interfere with the interpretation of the study results.
• Women who are known to be pregnant or who are intending to become pregnant over the course of the study.
• Women who are lactating.
• Major trauma or a surgical event within 2 months (or longer depending on trauma or event) and after consultation with PI. Has used antibiotics within the previous 2 months.
• History of an eating disorder (e.g., anorexia nervosa, bulimia nervosa, or binge eating) diagnosed by a health professional.
• Excessive coffee and tea consumers (> 4 cups/d).
• Donated blood within the last 3 months.
• Women who are taking an unstable dose and brand of hormonal contraceptives and/or a stable dose and brand for less than 6 months.
• Unusual working hours (working overnight).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Avocado meal plan; 2 meals and snack per day including one avocado in the meal, covering 80% of daily calories need.	Other: Avocado meal plan; American Diet with avocado
Placebo Comparator: Control meal plan; 2 meals and snacks per day without the inclusion of avocado, covering 80% of daily calories needs.	Other: Control meal plan; American diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in serum biomarker: triglycerides	analyzed by McLendon labs	baseline and 4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in serum biomarker: insulin	analyzed by McLendon labs	baseline and 4 weeks
Changes in serum biomarker: glucose	analyzed by McLendon labs	baseline and 4 weeks
Changes in HOMA-IR	Calculated from fasting glucose and insulin	baseline and 4 weeks
Changes in Muscle Insulin Sensitivity Index (MISI)	calculated using postprandial glucose and insulin concentrations measured by Randox clinical analyzer	baseline and 4 weeks
Changes in total cholesterol	fasting state, analyzed by Labcorp	baseline and 4 weeks
Changes in LDL cholesterol	fasting state, analyzed by Labcorp	baseline and 4 weeks
Changes in HDL cholesterol	fasting state, analyzed by Labcorp	baseline and 4 weeks
Changes in non-HDL cholesterol	fasting state, analyzed by Labcorp	baseline and 4 weeks
Changes in C-peptide	analyzed by McLendon labs	baseline and 4 weeks
Changes in free fatty acids	analyzed by Quest Diagnostics Lab	baseline and 4 weeks
Changes in GLP-1	analyzed by Luminex multi-target analyzer	baseline and 4 weeks
Changes in sleep quality	measured by the Pittsburgh Sleep Quality Index (PSQI)	baseline and 4 weeks
Fructosamine	analyzed by Randox clinical analyzer	baseline and 4 weeks

Collaborators and Investigators

• Sponsor: Clinical Nutrition Research Center, Illinois Institute of Technology
• Collaborators: Hass Avocado Board
• Investigators: Principal Investigator: Britt Burton-Freeman, PhD, Food Sci and Nut Programs

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 28, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: May 28, 2026
• First Submitted That Met QC Criteria: May 28, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 28, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Insulin resistance; Triglycerides; Glucose metabolism; Lipids metabolism
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Hyperinsulinism; Nutritional and Metabolic Diseases; Insulin Resistance; Prediabetic State
• Other Study ID Numbers: IRB-2026-34

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No