Even if we assume weight loss is all about calories in/out, it's still intellectually bankrupt to say "a calorie is just a calorie," since you're not factoring in satiety. 2000 calories of white bread and sugar is just going to make you hungry enough to eat another 500,000,000,000 calories. 2000 calories of real food will leave a lot of people satisfied for hours on end.
“The whole concept of a macronutrient, like that of a calorie, is determining our language game in such a way that the conversation is not making sense." - Dr. Kurt Harris