I don't think there's a transcon (i.e. between YVR/YYC/YEG and YYZ/YUL/YOW and LAX/SFO and YYZ/YUL) other than the Red Eyes that does not provide a full meal in J irrespective of the actual meal hour times. It's always a breakfast until about 10a, then a lunch until 4p or so, and then dinner on every flight thereafter. Often the lunch and dinner are identical offerings, though in the summer (and on E90s which have no hot kitchen facilities) it can be a large cold plate for lunch. At least that's been my experience over the years.