Check the Isuzu Alterrra Thread.

They say this is the most fuel efficient among the SUVs in the market - Fortuner, Everest, Santa Fe.

Though it is not the most powerful.

Fortuner is the most powerful on the 3.0L Displacement followed by Everest.
So I guess Isuzu tweaked the engine - Thought not the most powerful, but the most fuel efficient.