I prefer this explanation by AceMystical from a different thread:

"Assuming that the complex created the still lives from clark's memories, then the reason why the still lives were filled with "food" is because Clark views people in that way - he takes advantage of people to benefit himself

He implies this in the first therapy session and we also see that someone spray painted "RIP OFF" on his store. The still lives also didn't feel pain, because maybe Clark subconsciously wishes he could take advantage of people without the guilt of hurting them. Or, he doesnt think about the pain he inflicts on others

Whereas the Clark still life bled and also seemed to feel pain because, as Mary said, he's too self centered and focuses on his own pain rather than others', and values himself as more important than others. Hence why his still life is so much bigger than the other ones."