I remember Energen Rolls. Were they from the 60s? or the 70s? - I'm not sure.- They were claimed to help with 'slimming' and were intended to be eaten in place of bread. They were roughly spherical, if I remember correctly, and 'slimmers' cut them in half and spread each half with butter - or more likely, a 'low-calorie' butter substitute 'low-fat' spread - and with other fillings such as what would normally go into a sandwich.
And again, if I remember correctly, they were made of cellulose! - more akin to wood than to what we think of as food! But they had been processed to be light and airy and easy to eat. - Energen Rolls were not really food for people, even if the people were 'slimmers'. Not being termites, people could not digest cellulose and so could not obtain calories or indeed any nutrition from these early junk foods.
But to lose excess weight, you don't need to play tricks on your body and to fool your stomach into thinking it's had a satisfying meal when it's really only had pretend food. The easiest, safest, fastest way to lose excess weight is to eat real food - the sort of food our paleolithic ancestors ate millions of years ago. That is the sort of food on which our bodies evolved and so it the food best suited to our species. - Leave the cellulose for the termites!
I don't know which species to suggest you leave the low-fat spread to! - It is a laboratory-invented concoction on which no species evolved. - Likewise artificial colorings and flavourings and other non-food additives. - Steer clear of them; they are up to no good, you may be sure! - Go for fresh foods, home-cooked and unsalted, not factory-produced processed junk.