When I go to mac donalds, I get a hamburger and a diet soda (I don't really care for the fries).
Makes sense for me, a 500-600 calorie meal. I't a nice lunch, tastes good (all beef, even MCD, is awesome this side of the world), and even has lettuce and tomato.
A standard McDonalds hamburger does not come with lettuce and tomato. Catsup, mustard, pickle, minced onions. Has 240 calories.
In your example, that double big mac has 700 calories.
A Big Mac has 530 calories. Not sure what a double Big Mac is since it isn't a standard part of McDonald's menu. By itself a Big Mac is fine now and then but people rarely eat just a Big Mac. Usually they have some fries and a sugar loaded soft drink too. This easily can get the meal over 1000 calories as you mention which is about half the daily caloric intake for an adult male.
Not a diet meal, but not that excessive. It even has a lot of lettuce, which is good against blood sugar spikes, esp. a good thing for most fat people.
No burger sold by McDonalds has "a lot of lettuce". It has at most a small piece (possibly shredded) the size of the bun. That is not a lot of lettuce using any reasonable definition of the word "lot". Furthermore to get enough fiber to actually affect blood sugar levels you would have to eat several cups of the stuff, far more than is in any McDonalds burger.