The aim of my research is to further develop our understanding of how obesity leads to the development of type 2 diabetes (T2D). In Canada, the number of individuals who suffer from T2D has almost doubled in the past 10 years, with individuals who are 65 years or over having the highest rate of new diagnosis. Individuals with obesity are two times more likely to develop T2D than healthy weight comparisons, however not everyone who is obese develops T2D. Recent evidence has indicated that changes of the cellular activity in fat tissue may be to blame. Fat tissue from different regions of the body can vary greatly in inflammatory markers, immune cell presence and fat cell size and number, all of which can be related to insulin resistance. The objectives of my thesis project are to compare the effects of obesity and T2D on regional inflammation, immune cell presence, and fat cell characteristics and to determine how weight loss modulates changes in these outcomes. Furthering our knowledge in these areas will help to improve obesity and T2D prevention and management programs, promoting increased quality of life and healthier aging.