It depends on context. If you are dealing with a percentage of overall types of ingredients by volume without changing the variety of ingredients you would probably use "less". Like if you reduced the mix of milk related ingredients. You would use "fewer" to indicate that the number of individual ingredients had changed. Like if they got rid of two of the ingredients of an original ten.

This could be a category error?

[–] Underwaterbob@lemm.ee 1 points 5 months ago (1 children)

I guess it depends on if it is a case of there having had been 97 of 100 ingredients having been naturally derived and now only 91 of those ingredients are such. Which admittedly seems unlikely.

[–] Drivebyhaiku@lemmy.world 2 points 5 months ago

I mean it could be using the percentages of another number. Like if there's 20 ingredients and you drop one it's a 5% reduction or if you added other non natural ingredients that would cause the percentage to drop... But whether it's less or fewer would depend on information we don't readily have because we don't know if it's ingredients by volume or of it's a reformulation of ingredients... and may be at the crux of this grammatical problem depending on what you assume is going on?