this is more or less the message that Lou Schuler and Alwyn Cosgrove convey in the recently published book “The New Rules of Lifting for Abs” (Avery, 2010). A very interesting one if you’re looking for an entertaining reading.
Schuler, an award-winning fitness journalist and one of the authors of the book, confessed that he hasn’t done a single crunch in at least ten years "The idea of doing crunches and sit-ups is to make the abdominal muscles bigger," he told.
"But we all have muscles there. My son had a six-pack for most of his childhood, without doing a single sit-up. He was just a skinny, active kid."
We all know that diet is far more important than exercise if you want a six (or even eight) pack. Most guys also probably don't realize that the most effective moves for chiseling the belly aren't crunches or sit-ups (which can actually do more harm than good). In fact, the best exercise to target your gut does the exact opposite of a crunch, and that is a plank!