The project will characterize human gut microbiome response to two different diets and the possible physiological and biochemical implications of such response on cardiometabolic risk factors. The study will use controlled-feeding, systems-biology, metagenomic, and metabolomic approaches to examine American dietary patterns.

The study will use controlled-feeding, systems-biology, metagenomic, and metabolomic approaches to examine American dietary patterns.

Inclusion Criteria:

• generally good health status based on one routine physical in the past 15 months, current health status
• normal HbA1C, weigh 110 lb or more
• Age 50 years or more, generally healthy, all races and both sexes
• generally practicing a meat-based dietary pattern, do not have any special dietary requirement, and
• willingness to comply with the study protocol, including on-site meal consumption and sample/data collection.

Exclusion Criteria:

• medication usage, probiotic, long-term antibiotic, and tobacco/drug/alcohol use
• Not on any special diet within 3 months of recruitment, and do not have any intention to lose weight.
• impaired kidney functions
• Active history of cancer, diabetes, heart, liver, and kidney diseases
• major gastrointestinal disorders in the past 3 months
• history of heart attacks or stroke
• Unable to meet in-person visit requirements for dining, picking up meals, and tests
• Any mental health condition that would affect the ability to provide written informed consent.
• If they had not had a routine health checkup during the 12 months prior to recruitment.
• If they were unwilling to abstain from taking nutritional supplements, alcohol, non-study foods, and beverage during the study period.