This research focuses on the public's sentiment towards the topic of fitness, with the Online Social Network (OSN) Twitter used as the source of data collected and analysed. Having a strong passion for fitness myself, I wanted to see how in the growing access to gyms and the marketing of the "perfect body", how ones sentiment changes over a period of time whilst attempting to achieve such goals. From the analysis of over 23 million tweets collected between late December 2013 and early February 2014 a number of trends are identified and discussed within this book.