I don’t know whether por quilo restaurants are a genuine Brazilian invention, but they are one of those pleasant surprises visitors to Brazil will come across.
Basically, in a por quilo restaurant you pay according to the weight of what you put on your plate. You join the queue, grab your plate, help yourself to tons of delicious food, and at the end of the food counter, rest your plate on a balance. The display will automatically show the weight of the food contained on your plate as well as the price you will pay for it.
There are por quilo restaurants everywhere. You will recognize them when you see the por quilo sign, often accompanied by the cost per 100 grams of food: “POR QUILO: R$1,90“. In this example, for each 100 grams of food you put on your plate, you will pay R$1,90.
Drinks are paid for separatedly. Desserts might or might not be included in the por quilo system – when they are not, you pay a fixed price for them.
As well as por quilo restaurants, there are also por quilo ice-cream parlours. Can you imagine it?