Why would fast food burgers be bad/cause acne if they are char-broiled and not fried?

Because of the fat content in the burgers, how they are cooked is irrelevant if they are packed with fat and preservatives and unnatural ingredients . Most people will use an 80/20 meat which means 80% lean 20% fat , that's the normal for say a burger . But fast food places don't want to spend the money on that and it is cheaper to do a higher fat content.. Because the burgers are just so packed with unnatural things and junk they have side effects on your body and therefore your skin.