I don't think it works quite like that but I know where you're coming from OP. I've heard before that pheromone output has the most influence in women liking you but women don't work purely off of what she smells. She has eyes, she has ears, etc. She also has a brain and a conscience, which she will use to help determine whether or not you are a good enough mate.
>Why SHOULD NOT a thin woman crave a guy w/ a belly?
Depends on who has the belly if you ask me. If you look like the guy from your picture, OP, the large belly is complemented by his other large features. If you're some fat fuck sitting at the computer munching on cheetos, you probably have a high fat percentage and a low muscle percentage, coupled with not enough hair on the body. Humans can associate those features with being unhealthy.
One thing that pisses me off is when people talk about humans and sexuality, their number one thing to go to is how "PRIMITIVE" the mind is. That we're just monkeys who see wide hips and a fat ass and go "OH MAN GOOD MATING MATERIAL I'M ATTRACTED TO THAT LET ME FUCK IT". I'm sure there are some people like that out there but we're not all that daft. Humans aren't so primitive that we immediately associate fat with fertility and tall height with power; everything has to be in a natural order. In reality, the face is the most sexually stimulating part of the body. That's what most men look at when they're masturbating to porn, is the face of the girl. If humans were SOOO PRIMITIVE, then there wouldn't be words like "butterface" in our nomenclature.
What makes a man a man ISN'T a state of mind, nor is it how he looks. It's a combination of both. Your mind will compliment your body just as your body will compliment your mind. That is, your mind will influence how your body looks just as how your body functions will influence how your mind works. They go hand in hand.