Lahti is not a food destination, but it has a small handful of decent restaurants and a friendly local kitchen. The market hall (Kauppahalli) at the centre is a good place to look for traditional Finnish ingredients — rye bread, salted fish, reindeer products, cheeses, berries — and a couple of small eateries inside the hall make a respectable lunch.
The harbour at the foot of the city has a strip of summer-only restaurants and bars; in winter most of these close down.