Hey, I have character with big fat belly and thin legs. I was planning to use normal splineIK or ribbon setup with squash and stretch. I actually don’t know the techniques for fat character or what things to take care of. Can someone suggest something which can make it better?
I consider moving the spine forward a bit on fatter characters because it looks better when they bend forward. Other than that I just add extra jiggle controls. In some ways fat characters can be easier than skinny characters because the volume loss when bending and twisting is much less noticeable. I would suggest making sure that the arms can bend down to the side without clipping through the midsection before building the control rig.
Thanks for the reply. Now I know what I have to search for. I will test it as soon as possible and will let you know what happened 
The further the verticies are from the bone that has the skin weight the less relevant the rotations will be. You will end up with some really unpleasant deformations. You can help this by not skinning to the spine itself but rather to a set of joints set out in the flesh further toward the surface. Have these joints follow the translation of their respected spine joint but rotate from their own position. This will help maintain volume. You could also do some interesting things with combinations of driven controls and dynamics to drive these bones for simulating a much more efficient jiggle than a jiggle deformer (an effect you could easily export as well).