When we are talking tonnes of fuel, it burns fuel to tanker fuel.
As a rule of thumb yes......but remember, only a small percentage of that extra tonne will be burnt... eg, on a SYD - MEL sector the extra burn is negligible - therefore most of the fuel remains for the next sector, on something longer then yes you might start burning into it a bit more..
However if you fly a little smarter the extra burn can be offset.
For example SYD-PER.... sometimes if you drop several thousand feet below the 100+ headwind, you can save time and make gas. Even though its well below optimum. Many longhaulers are so used to climbing for long range efficiency they refuse to consider the option of dropping so far below optimum. (Unless its for ride)