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.
Notice the word "I". When _I_ go, I have a hamburger (type not specified) and a diet soda (also not specified).
The hamburger I get is a McNifica, which, does have lettuce and tomato, alongside a largish patty. Looked it up, 541 kcal (http://www.mcdonalds.com.ar/mcnifica).
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.
You are missing the point at "usually". The GP was complaining about fat people _omitting_ the sugar, effectively keeping the caloric below insane ranges.