Perhaps memories of Post Fruit & Fibre are not exactly noteworthy, but that is probably because you did not live with a family who went through a fiber obsession phase. I do not remember the exact year it started. I would say the late 80s or maybe the early 90s. It started when some magazine article or TV special talked about how awesome fiber was for your health and every member of my family all bought into it at the same time, accept me of course.
The next day everything had fiber in it. White Bread? Gone! Breakfast Cereal? Super high fiber everything. As a consumer of much cereal, this hit me the hardest and I watched as my family moved from cereal to cereal trying to find something with fiber that was tasty. They finally decided on Fruit & Fibre and it became a staple for the entire run of the high fiber craze.
It was a pretty tasty, but my least favorite part was the flakes and I often just picked the fruit and nuts from the box and left the flakes for those less discerning.