Fructose: Substrate, Stimulus, or Both?

Inclusion Criteria: * Body Mass Index 22 to 35 kg/m2 * Prediabetic (HbA1c 5.7% to 6.5%) or hyperinsulinemic (fasting insulin ≥12 µIU/mL) but non-diabetic (fasting glucose \<126mg/dL and HbA1c \< 6.5%) ; or normal control (fasting insulin \<10 µIU/mL, fasting glucose \<100 mg/dL, and HbA1c \< 5.7%) Exclusion Criteria: * Pregnancy or lactation within the past six months * Type 1 or 2 diabetes mellitus * History of liver disease or aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 2x the upper limit of normal (ULN); * Fasting triglyceride or total cholesterol levels above 95th percentile for age and sex; * Hemoglobin or hematocrit below the lower limit of normal for sex; * Report of hepatitis or HIV infection; * History of cancer, use of any anti-diabetic medications or hypolipidemic agents in the past six months; * History of surgical procedure for obesity; * Self-reported change in body weight \>5% in the past six months; * History of other conditions known to affect insulin sensitivity and lipid metabolism; * Known intolerance to acetaminophen or components of the liquid test meals.