Well, if you isolate the take-off you probably use a bit less fuel, however if you take into consideration the whole flight you use a bit more as time to cruise altitude (optimum cruise) is longer. The amount isn't big (around 35 to 55 kg per flight for a B738) and certainly does not offset lower maintenance costs.
And crazy as it sounds, there are really people whos job it is to calculate stuff like that, weird way to make a living.