The Western diet pattern or standard American diet is a modern dietary pattern that is characterized by high intakes of meat, pre-packaged foods, fried foods, high-fat dairy products, eggs, refined grains etc. When considering the role of saturated fat, it may be prudent to advise limiting all foods that contain saturated fats, including unprocessed/minimally processed meat, eggs, whole dairy in addition to processed, pre-packaged foods; however, this reductionist approach fails to take into account the food matrix and overall diet in which these nutrients are consumed.

Epidemiological evidence suggests that increased modern, pre-packaged food consumption is a major risk factor for metabolic disease by promoting inflammation. Based on these data, the investigators hypothesize that the pro-atherogenic effect of the Western diet is caused by the pro-inflammatory effects of consuming large amounts of modern ultra-processed foods, and that consumption of a similar amount of fat from minimally processed beef, poultry, dairy, eggs, as part of an unprocessed diet will positively impact inflammatory markers and lipoprotein profiles of study participants when compared to a diet rich in modern ultra-processed foods.

Inclusion Criteria:

• Age ≥35 and ≤60 years;
• BMI ≥25 and ≤35 kg/m2;
• Weight stable in last 3 months (Loss or gain <4%);
• Consistent physical activity levels;
• Hemoglobin A1C (HbA1C) ≤6.4%;
• Fasting insulin; <15 µU/mL;
• Fasting plasma glucose concentration <126 mg/dl;
• Willingness to eat the food provided in this study;
• Subjects must be able to speak and understand English to participate in this study
• Own a smartphone or other mobile device capable of downloading the Garmin Connect app.

Exclusion Criteria:

• Diagnoses of active malignancy, congestive heart failure, diabetes mellitus, chronic obstructive pulmonary disease, thyroid disease or other metabolic disorders that influence metabolism;
• Evidence of impaired kidney function (Estimated glomerular filtration rate [eGFR] <44 mL/min;
• Regular use of medication that interferes with the measurement of study outcomes as determined by the study team (e.g., NSAIDs, corticosteroids);
• Consuming >14 drinks per week of >4 drinks per night twice/week for male; >7 drinks per week or >3 drinks per night twice/week for female;
• Use of cigarettes (or other tobacco products) or use of any other (recreational) drug in last 3 months;
• Engaged in high-level competitive exercise (e.g., marathons, triathlons, cycling, weight-lifting competitions etc.)
• Self-reported sleep duration <5 hours per night;
• Any inflammatory diseases (e.g. asthma, autoimmune diseases, coeliac disease, glomerulonephritis, hepatitis, inflammatory bowel disease, arthritis);
• Use of antibiotics in last 30 days;
• Pregnant or lactating women;
• Eating disorders (e.g., anorexia nervosa, bulimia nervosa, binge eating disorders etc.)
• Psychological disorders (e.g., clinical depression, bipolar disorders etc.);
• Strict dietary patterns (e.g., vegan, carnivore, kosher, low-carb etc.);
• History of stomach or bowel resection (other than appendectomy), gastric bypass or other bariatric weight loss procedure effecting absorption;
• Persons who are not able to grant voluntary informed consent;
• Persons who are unable or unwilling to follow the study protocol or who, for any reason, the research team considers not an appropriate candidate for this study, including non-compliance with screening appointments or study visits.

As this is feeding study with two very much different diets, participants and investigators were not blinded. The Core facilities that are analyzing de-identified coded samples and remain blinded to treatments.