Once again a Malaysian official not knowing what he is talking about. To get to the new search area 700 miles closer it would have flown slower at lower altitude not faster.
Higher speeds consume more fuel than lower speeds and MUCH higher speeds consume MUCH more fuel.
It SEEMS that maybe the pilot was in a rush to go somewhere and he burned much more fuel than he thought he would and therefore ran out of fuel and crashed.
That sounds logical but they argue that the faster speed consumes fuel at a faster rate which reduces the range so the aircraft falls into the sea further north.