Complex Effects of Dietary Manipulation on Metabolic Function, Inflammation and Health
Obesity, Insulin Resistance
About this trial
This is an interventional other trial for Obesity
Eligibility Criteria
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
Sites / Locations
- Washington University School of MedicineRecruiting
Arms of the Study
Arm 1
Arm 2
Arm 3
Arm 4
Arm 5
No Intervention
No Intervention
Experimental
Experimental
Experimental
Metabolically normal lean - Baseline testing only
Metabolically normal obese - Baseline testing only
Metabolically abnormal obese - Mediterranean diet
Metabolically abnormal obese - Low carbohydrate ketogenic diet
Metabolically abnormal obese - Plant-based very-low-fat diet
Metabolically normal lean - Lean individuals that have good glucose (sugar) control, normal plasma triglyceride (fat) levels and a low liver fat content. Dietary intervention - None.
Metabolically normal obese - Persons with obesity that have good glucose (sugar) control, normal plasma triglyceride (fat) levels and a low liver fat content. Dietary intervention - None.
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver. Dietary intervention - A nutritionally balanced diet that includes fruits, vegetables, fish, beans, whole grains, and olive oil with approximately 50% of daily calories coming from complex carbohydrates, 30% of calories from fat, and 20% of calories from protein.
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver. Dietary intervention - A very-low-carbohydrate, adequate protein, high-fat diet containing 20 grams of carbohydrate or less per day (about 5% of calories), derived mainly from vegetables.
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver. Dietary intervention - A plant-based diet high in complex carbohydrates and low in fat, protein, and sodium, with approximately 70% of daily calories from carbohydrates, 15% from fat, and 15% from protein.