This is pretty much exactly right. The only way to lose weight is to be at a caloric deficit. The tricks such as cutting out soda for water or limiting carbs severely are basically just quick cheats to get that deficit.
You are looking at that the wrong way. Switching soda for water isn't a diet cheat, it's the easiest, best possible lifestyle change Druff can make. Like, its a permanent change that can make him lose and keep off weight, not something he has to keep track of.