I didn’t say it was better, I doubt it would be worse. You vastly overestimate how much variety, or vegetables, are necessary to maintain health. The following are nutritionally complete; if you eat them you will not get any deficiency diseases, potatoes and milk, rice and beans, peanut butter and bread. Note that they all include a source of carbs and protein, like burgers. Hell, as long as you eat fatty meat you can eat nothing but meat with no ill effects on health. Over the course of a day you’d get enough lettuce and tomato to stave off deficiency diseases, and that neglects ketchup, otherwise known as concentrated tomato.
The problem of a western diet isnt one of deficiencies though. No doubt if you have enough burgers you'd get enough nutrients but the amount of meat and carbs would be massive.
This [1] suggests vitamin C would be the big problem for a Big Mac (1% RDA) followed by vitamin A (4% RDA). 100 burgers a day sounds quite hard to stomach, so the question becomes how bad the western diet is.
