I grew up in the 60’s, in a fat family. My folks were always on one diet or another. I remember METRACAL, in a can. Some of the concoctions they made as substitutes for the food they really enjoyed were pretty bizarre. I think many of them were from Weight Watchers cookbooks of that time.
I remember my mom quartering small white mushrooms, maybe adding a little soy sauce (sodium had not yet been demonized)and baking them until they shriveled up to nothing. This particular treat was called "popcorn". Yeah, right.
Lots of cottage cheese & unadorned tuna, too.
Anybody else remember, or have your own, "dietetic" foods?