Like Swedish English has quite a few words where the plural is the same as the singular., such as deer, sheep, fish, food. However, in current use of English many people born in nominally English speaking countries don't know this. DL at least tries to retain a few such items of correct grammar.
- We eat different food = the food that you and I eat is different from the food that others eat.
- We eat different foods = The food that I eat is different from the food that you eat.
Which does the Swedish mean?
Both "food" and "foods" are accepted translations, but personally it makes me think of the second one. I would translate the first as "Vi äter (en) annan mat (än dem)" ("än dem" = "than them").
Because "mat" is the same in singular as in plural". It's like "water" in English. You can't have one water, and you can't have "en/ett mat". However, you can have a lot of water, "en massa mat".
I hope this to some extent answers your question :)
For some stupid reason I still sometimes translate 'mat' into 'meat' instead of 'food' :(
Not so stupid. In older English, "meat" was the general term for food. Cf. "one man's meat is another man's poison."
It is the same for the French word "viande", from Latin "vivenda/vivanda", which originally was a general term for food. It replaced the original term "carn/charn/char/chair" = "flesh"
So is "mat" plural here? Is it one of the very few gender nouns which don't take any ending in the plural, like mil, fot, tum (as measures)?
Even with glances of explanations down here I admit I'm still not sure why 'olika' and not 'olik' (if olik is indeed degree zero of the adj) : it mat here simply considered as a plural ? Or is it basically the way it works for uncountable concepts in Swedish ?
I'm no expert, but it seems that 'mat' is being construed as plural. The Swedish 'mat' seems to be like the English 'food' in that you can use it as either a count or a non-count noun. So the Duo translation could also read 'We eat different foods', I would say.
The first letter "O" implies "the opposite". Möjlig/omöglig. Vanlig/ovanlig. Lik/olik.