'Nimble. Real bread, but lighter,' was the slogan in this early 70s advert. The advert, I remember, was of a lovely young woman (...who was older than I was at that time!) in a balloon and the song 'I can't Let Maggie Go' by Honeybus was the accompanying background song.
Nimble bread was for marketed towards slimmers, I think, but when we had it, it was usually cos there was no 'proper' bread left in the shop. Though I didn't need to lose any weight then, this bread made great, crunchy toast!