JanM, I also have heard a few times that it is ideal to feeds
adult dogs once a day, although I have never really researched it before or bothered to look into it...
I always do 2 meals a day for my smaller (and senior) dogs. Although one is lighter (more of a snack) then the other. I feed raw and usually give a meal in the morning that is about 75% of their total daily requirement, and then around 25% in the evening.
For my bigger girl, who is also younger (at 2 years old), I sometimes will do one meal a day and then just give her a bone or something to chew on in the evening.
I also have read in several places, some people fast their dogs one day a week. Personally, I have not done this, although I do find some days my dogs just don't seem too hungry and seem to naturally "fast" themselves by eating very little in a day.
Then the next day they eat normally.