Why does being thin make you look taller? While being fat somewhat makes your legs look shorter?
It's a kind of optical illusion created when our mind tries to "normalize" a person's body size. This effect happens most often when we see people on TV or in a movie when we might not see other people to compare them to. When we see a see a really thin person, our mind wants to see that person with a "normal" sized body, which means all his/her body dimensions seem larger, including height, to stay proportional. Likewise, when we see a obese person, our mind wants to "normalize" him/her size by reducing not only his/her breadth dimension, but also the height, again to stay in proper proportion.
nnaybe cause the fat isnt getting in the way