Look at the differences in the organs of these two people. The left person has a layer of fat surrounding all the organs, I mean look at his/her heart! There is no way all those organs can efficiently do their job when they are that compacted. Next take a look at the joints of both people, especially the ankles. The human body is not designed to support that much extra weight.
Changing My Life, One Step at a Time
Source: Emily James Fitness