Eligibility Details:
Inclusion Criteria:
- Metabolically normal lean subjects must have a body mass index (BMI) 18.5-24.9 kg/m2,
intrahepatic triglyceride (IHTG) content ≤5%, serum triglyceride (TG) concentration
<150 mg/dl, fasting plasma glucose concentration <100 mg/dl, 2-hr oral glucose
tolerance test (OGTT) plasma glucose concentration ≤140 mg/dl, and hemoglobin A1C
(HbA1C) ≤5.6%.
- Metabolically normal obese subjects must have a BMI 30-49.9 kg/m2; IHTG content ≤5%,
serum TG concentration <150 mg/dl, fasting plasma glucose concentration <100 mg/dl,
2-hr OGTT plasma glucose concentration ≤140 mg/dl, and HbA1C ≤5.6%.
- Metabolically abnormal obese subjects must have a BMI 30-49.9 kg/m2; IHTG content
≥5.6% and fasting plasma glucose concentration ≥100 mg/dl or 2-hr OGTT plasma glucose
concentration ≥140 mg/dl or HbA1C ≥5.7%.
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);
- cancer or cancer that has been in remission for <5 years;
- polycystic ovary syndrome;
- 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);
- severe anemia;
- regular use of tobacco products;
- excessive consumption of alcohol (≥3 drinks/day for men and ≥2 drinks/day for women);
- 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;
- 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