This thesis investigates the complexity of the obesity phenotype by characterizing the inflammatory status of Metabolically Healthy Obese (MHO) individuals. More specifically, this work has examined circulating inflammatory markers in MHO individuals and compared it to Lean Healthy (LH) and Metabolically Abnormal Obese (MAO) subjects. Thirty participants (n=10/group) were recruited as part of the Diabetes Risk Assessment (DRA) study, and classified according to adiposity and metabolic status. Despite a similar level of adiposity compared to MAO individuals, MHO subjects presented a more favourable inflammatory profile. Specifically, MHO individuals had levels of hsCRP and IL-6 comparable to LH subjects and lower than MAO subjects. Also, MHO subjects presented similar levels of high molecular weight adiponectin as the MAO group, but PDGF-ββ levels were intermediate to those of the LH and MAO groups. Overall, the distinct inflammatory profile observed in MHO subjects demonstrates the unique status of these individuals, reinforcing that obesity is a complex and heterogeneous phenotype. / Public Health Agency of Canada, Ontario Graduate Scholarships, Queen Elizabeth II Graduate Scholarships in Science and Technology, Canada Foundation for Innovation