Effect of Moderate Weight Loss in Metabolically Abnormal Lean Subjects

Obesity is associated with a constellation of cardiometabolic abnormalities (including insulin resistance, elevated blood pressure and dyslipidemia) that are risk factors for diabetes and cardiovascular disease. Weight loss can improve all of the cardiometabolic abnormalities associated with obesity. Up to \~25% of lean people (Body Mass Index \[BMI\] 18.5-24.9 kg/m²) have many of the cardiometabolic abnormalities associated with obesity and are referred to as metabolically abnormal lean (MAL) people. However, the MAL phenotype is not well characterized, and it is unclear whether weight loss has beneficial metabolic effects in already lean people. Accordingly, the goal of this study is to: 1) carefully phenotype MAL people and 2) evaluate the effect of moderate (8-10%) diet-induced weight loss in MAL people. This will be investigated in 15 MAL (defined as having 2 or more of the following: intrahepatic triglyceride (IHTG) content ≥5.6%, glycated hemoglobin ≥5.7%, fasting plasma glucose concentration ≥100 mg/dl, 2-hr oral glucose tolerance test (OGTT) plasma glucose concentration ≥140 mg/dl, homeostatic model assessment of insulin resistance (HOMA-IR) ≥ 2.5) men and women. Only lean people who have a BMI ≥21.0 but \<25.0 kg/m² will be asked to lose weight to avoid the risk that participants become underweight (BMI \<18.5 kg/m²) during weight loss therapy.