Why can't i suck in my stomach anymore?

Abd. fat vs. water: The healthiest location for fat storage is under skin. However, the most active (in & out) fat stores are around out internal organs & blood vessels, called visceral fat. When not lean, the additional fat is stored in visceral locations, most within abdomen. When abdomen has enough additional fat, edema (cirrhosis), pregnancy, etc., then people are no longer able to "suck in" as much as before.

May be: six pack abdomen or obese abdomen? Need more information or clarification