Food and Metabolism Study

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 Illinois Tech 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). Investigators will determine if participants qualify for the study at the Screening Visit by the following measurements: * General measurements: height, weight, body composition, waist circumference, blood pressure, vitals 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. Investigators 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 participants 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. Investigators 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 (https://asa24.nih.gov/). 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 (https://asa24.nih.gov/) 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, Investigators will proceed to an exam room to measure: Anthropometrics: Investigators will measure weight, waist circumference and body composition. Vital signs: Investigators will check their blood pressure, heart rate, and body temperature using standard clinic devices. Once Investigators have collected measurements, they 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. Investigators will use an indwelling catheter (IV). This means Investigators will use a needle to put a thin tube in their arm or hand, from which Investigators 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 Investigators 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, Investigators 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. Investigators 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 participant 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. Investigators will collect materials and ensure they are complying with the study protocols, and assess if there are any difficulties Investigators 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 (https://asa24.nih.gov/) 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