is it a good idea to grill sliced tomatoes with no oil or any kind of fat?

I like tomatoes and hot food but I don't like to add much fat to my food, be it oil or butter. I won't use lard.

Am I going to ruin the sliced tomatoes by grilling them on a pan just with salt and pepper?

I'm talking about 4 to 6 regular tomatoes per serving, half an inch thick slices.