Basically, never order the breakfast platter.
McDonald's: Big Breakfast with Hotcakes (1090 calories)
FYI, without the hotcakes the calories drop down to 740 for the Big Breakfast.
Wendy's: Dave's Hot 'N Juicy™ 3/4 lb. Triple (1090 calories)
As a side note, one of these roughly equals to about 3.75 of Wendy's Jr. Cheeseburgers, which are 290 calories each.
KFC: Chicken Pot Pie (790 calories)
Also, if your dare, some of the soft drinks offered in 64 oz. will come in at a whopping 880 calories.
Carl's Jr.: The 1/2 lb. Guacamole Bacon Thickburger® (1210 calories)
As an alternative you might choose The 1/3 lb. Low Carb Thickburger® instead, since it only has 450 calories.