Eating Ambrosia all the time is a great way of being happy without always staying young on vacation lots (something I personally like), but one thing to note to is that even you get the Ambrosia from the food replicator as a nomal meal (not even tasty or perfect) the quality of the disk can increase though, if you made it more often. Although it is not very high, as far as I know. Because my sims has made it a couple of times and the standard value of 75 has only increased by 5 to be 80.
Well, although it is not much, it is better than nothing I think.