It's been over 20 years since I've eaten at McDonalds. I once removed the "meat" patty from a Big Mac and tried eating it sans bun, cheese or sauce. I wouldn't recommend that to anyone.
That said, if someone wants to eat a 300-calorie piece of tire rubber, that's their business. Last night I ate a 14-inch, 3000 calorie pizza (2500 for the pizza, 500 for the extra cheese I added). If the food police had their way, I'd be in prison for doing that.