High fasting insulin concentration (hyperinsulinemia (HI)) is considered as a compensatory response which enables the maintenance of blood glucose concentrations in the presence of tissue insulin resistance. Obesity is thought to be a key driver for HI, prediabetes and overt diabetes. However, the United Kingdom Prospective Diabetes Study (1) showed a third of patients with type 2 diabetes had a BMI within the healthy weight range (<25g/m2), suggesting that factors other than obesity are important. We aimed to assess the metabolic health of non-obese apparently healthy young adults to inform on the factors driving HI and prediabetes. To date, we have screened 361 individuals (204 females; 157 males, age: 24.8 ± 4.4 y, BMI: 23.7 ± 3.0 kg/m2) via oral glucose tolerance test with plasma insulin, fasting blood lipids, blood pressure, body composition and dietary intake. 11% (n=40) were found to have prediabetes (Impaired Fasting Glucose (n=24) and/or Impaired Glucose Tolerant (n=26)). Normal glucose tolerant individuals (n=321) were classified as either having normal fasting insulin (n=274) (Females ≤40.47 pM; Males ≤56.82 pM) or fasting HI (n=47). Whilst BMI was largely considered to be within a normal range within the HI group (25.0 ± 3.3 kg/m2), there was a significantly higher body fat percentage in both the HI and prediabetic group as compared to the normal group (P < 0.05). Similarly, fasting triglyceride was significantly elevated in the HI group compared to the normal group (P < 0.05). These data highlight the high prevalence of prediabetes in non-obese young adults. Furthermore, fasting HI is present despite similar BMI and blood glucose concentrations to the normal insulin group. Overall, obesity-independent factors should be considered when examining the mechanisms driving adverse metabolic health outcomes in young adults.