Clinical Research Directory

Inclusion Criteria: * Age 40-65 years * BMI 25 to 40 kg/m2 * HbA1c 5.7-6.4% * Low habitual intake of peanut butter (\<0.5 Tablespoons/day on average) * Have a smartphone device or be willing to use one provided by the study Exclusion Criteria: * Hemoglobin \<13.2 g/dL for men or \< 11.7 g/dL for women at screening * Fasting triglycerides \>350 mg/dL at screening * LDL-cholesterol ≥190 mg/dL assessed by the Martin-Hopkins equation at screening * ≥10% change in body weight within the 6 months prior to enrollment * Blood pressure \>140/90 mmHg at screening * Diagnosed type 1 or type 2 diabetes * Takes any (prescription or over-the-counter) anti-hypertensive, lipid-lowering, glucose-lowering or body weight altering drugs * Intake of supplements that affect the outcomes of interest (i.e., lipids, blood pressure, glucose, body weight, and microbiome) and are unwilling to cease during the study period. * Unwilling to refrain from starting to take any supplements, vitamins, nutritional products, or health foods that are not prescribed by a doctor for the duration of the study * Self-reported history of diagnosed liver, kidney, or autoimmune disease * Self-reported history of a prior cardiovascular event (e.g., stroke, heart attack) * Self-reported history of diagnosed neurological disease (e.g. Alzheimer's Disease, Parkinson's Disease, Multiple Sclerosis) * Current pregnancy or intention of pregnancy within the next 12 months * Lactation within the prior 6 months * Peanut allergy/intolerance/sensitivity/dislike * Antibiotic use within the prior four weeks * Oral steroid use within the prior four weeks * Use of tobacco or nicotine-containing products within the past 6 months * History of cancer at any site within the past 10 years (eligible if ≥10 years without recurrence) or non-melanoma skin cancer within the past 5 years (eligible if ≥5 years without recurrence) * Participation in another clinical trial within 60 days of baseline * Currently following a restricted or weight-loss diet * Prior bariatric surgery * Intake of \>14 alcoholic drinks/week and/or not willing to avoid alcohol consumption for 48 hours prior to test visits * Does not speak and/or understand English * Unwilling to refrain from donating blood and/or plasma during the study * Weight \<110 lb * Unwilling to contact study staff before enrolling in other health-related research and avoid participating in any research that may interfere with this study * For individuals taking thyroid medication: abnormal thyroid stimulated hormone (TSH) concentration, or change in dose of thyroid medication within the last 6 months * Principal Investigator discretion related to the potential participant's ability to adhere to the study requirements, including being able to come to attend visits