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.
Try it and see - cooking is meant to be a learning experience!
That said, a little fat used just right (even distribution helps - mix it up in a bowl beforehand) can go a long way. Tomatoes are plenty healthy, and a little oil won’t ruin that any more than a little dressing won’t ruin a salad’s healthiness.
The best dishes have a good balance of fat, salt, acid and heat. If you’re cooking a bunch of tomatoes, I’d use a small amount of olive oil, salt or soy sauce, maybe a small dash of balsamic if you want an extra dimension of acid (the tomato supplies its own too), and garlic powder (or skip the salt and use garlic salt) for a little heat.