That's not entirely true. Weight is the least important factor. The fact is that it takes a lot more energy to turn those wheels because the weight is farther from the centerline. So it obviously takes more energy to stop them.The energy is seen in the form of heat, which is a braking systems enemy.
Most of these "donk" cars don't ever take that into consideration because it looks "cool".
You may think your brakes work fine, but in reality they are working harder than they were engineered to. The disk/drum setup was barely (that's being generous) adequate for stock wheels diameters and power levels. They may suffice, but they are not operating as intended. Thus, when you add a 5" larger diameter wheel (more reciprocating mass) you should invest in a brake upgrade. Otherwise, you are putting your own safety, and others, at risk.
But hey, its your car, do what you want