Successful use of the DxDDP without tying yourselves up with 3 sit down meals per day means that you'll be eating 2 larger meals, one of which is a signature. With the amount of food that's standard on any Disney table service meal, and the two snack credits per person per day, there is no way you will ever go hungry.
My wife and I did the DxDDP for 5 consecutive years. We'd typically use a snack credit to grab a pastry before we headed off to the park *if* we felt hungry at breakfast (which we ordinarily were not). We'd then have an early lunch, usually 11:30 or 12:00 at a table service in the park, followed by a late, usually 7:30pm or 8pm signature dinner.
It's hard to go wrong with any of the signature restaurants, with the exception (flame suit on) of LeCellier, which is a signature due to price alone. We've had great meals and experiences at California Grill, Narcoossee's, Citrico's, Artist Point, Monsieur Paul, Yachtsman, Hollywood Brown Derby, and Jiko.