What’s the difference between 100 calories of peanut butter and 100 calories of bread?

Okay so I'm trying to gain weight in a healthy way, where it doesnt ALL just go to my stomach (by the way, does anyone have any tips on how to do that?) and i have to eat 2500 calories a day according to my doctor, which is nearly impossible for me...but anyways...i was wondering if eating 100 calories of peanut butter would be the same as eating 100 calories of bread or of something else like sorbet or something...so i guess my question is, are there different types of calories? Like would 100 calories of peanut butter make me gain more fat than 100 calories of sorbet? What about the difference between 100 calories of a fatty food and 100 calories of a carb-heavy food? Or is it all the same?