Cheers. Do you have any citations handy for the old studies? I’m open to being wrong, but after some very brief searching and reading I’m skeptical that they properly controlled for increased feed intake (possibly due to palatability) to conclusively determine that some other mechanism was at play
DALDERUP, L., VISSER, W. Effects of Sodium Cyclamate on the Growth of Rats compared with other Variations in the Diet. Nature 221, 91–92 (1969) https://doi.org/10.1038/221091b0
But of course the manufacturers of feed additives also extensively studied which artificial sweetener compositions achieve body mass gain / feed efficiency increase for which group of animals. There is an extensive review e.g. on pigs here:
