Numerous methods have been validated to assess obese individuals’ physical activity in free-living conditions. Subjective measures are useful assets for physical activity estimations patients, despite many limitations. More legitimate estimations are obtained using objective measures such as accelerometry (minute-by-minute activity recording) as it provides real time data in human movement. Accelerometers can discern inter-individual variability and quantify patterns of postural allocations for continuous periods of several days. Our goal is to help quantify how bariatric surgery patients evolve in their day to day activity after surgery using accelerometers.