Yes, your body type can change the way your mattress feels. Heavyweight sleepers tend to compress the memory foam layers more deeply, and thus prefer a very soft mattress (like the AS5, which has five layers), or a fairly firm mattress (like the AS2). Lighter sleepers typically like soft beds since they don't compress the mattress much at all. Again, your weight and sleeping position both affect which firmness you prefer. No matter your body type, make sure your mattress uses a base that will not sag. A great mattress holds up under lots of pressure without losing support.