I do all my own butchering. I never add any fat to any of my grind. When I make burger patties,, I use a george foreman, or a skillet. Not on a normal outdoor grill. I do often add an egg as a bit of a binder when I'm doing it,,, as well as the seasoning.
I don't have any issues.
I prefer my meat to not have "processed" foods added whenever we can. Beef, pork etc fat has to obtained from a grocery store,,, but we still don't know how it was raised & what it was fed. After Miss Penny's cancer surgery,, we have really watched a lot of what we eat.