Inclusion Criteria:

• * Metabolically normal lean subjects must have a BMI ≥18.5 and ≤24.9 kg/m2; Obese subjects must have a BMI ≥30.0 and ≤50.0 kg/m2
• * Metabolically normal lean and obese subjects must have intrahepatic triglyceride (IHTG) content ≤5%; plasma triglyceride (TG) concentration \<150 mg/dl; fasting plasma glucose concentration \<100 mg/dl, 2-hr oral glucose tolerance plasma glucose concentration \<140 mg/dl, and hemoglobin A1C ≤5.6%
• * Metabolically abnormal obese subjects must have intrahepatic triglyceride (IHTG) content ≥5.6%; HbA1C ≥5.7%, or fasting plasma glucose concentration ≥100 mg/dl, or 2-hr oral glucose tolerance test (OGTT) plasma glucose concentration ≥140 mg/dl.

Exclusion Criteria:

• * Medical, surgical, or biological menopause
• * Previous bariatric surgery where the gastrointestinal tract is reconstructed such as Roux-en-Y, sleeve gastrectomy and biliopancreatic diversion surgeries
• * Laparoscopic adjustable gastric band (lab band) surgery within the last 3 years
• * Structured exercise ≥250 min per week (e.g., brisk walking)
• * Unstable weight (\>4% change during the last 2 months before entering the study)
• * Significant organ system dysfunction (e.g., diabetes requiring medications, severe pulmonary, kidney or cardiovascular disease)
• * Polycystic ovary syndrome
• * Cancer or cancer that has been in remission for \<5 years
• * Major psychiatric illness
• * Conditions that render subject unable to complete all testing procedures (e.g., severe ambulatory impairments, limb amputations, or metal implants that interfere with imaging procedures; coagulation disorders)
• * Use of medications that are known to affect the study outcome measures (e.g., steroids, non-statin lipid-lowering medications) or increase the risk of study procedures (e.g., anticoagulants) and that cannot be temporarily discontinued for this study
• * Use of antibiotics in last 60 days
• * Smoke cigarettes \> 10 cigarettes/week
• * Use marijuana \>2 x/week, or use of illegal drugs
• * Men who consume \>21 units (e.g. glass of wine or bottle of beer) of alcohol per week and women who consume \>14 units of alcohol per week
• * Pregnant or lactating women
• * Vegans, vegetarians, those with lactose intolerance and/or severe aversions/sensitivities to eggs, fish, nuts, wheat and soy, and/or any individuals with food allergies that induce an anaphylactic response
• * 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