Finnish foods often use wholemeal products (rye, barley, oats) and berries (such as bilberries, lingonberries, cloudberries, and sea buckthorn). Milk and its derivatives like buttermilk are commonly used as food, drink or in various recipes. Various turnips were common in traditional cooking, but were replaced with the potato after its introduction in the 18th century.

A large midday meal in a rural household in Finland may include fish baked in a rye loaf (leipäkukko), potatoes (peruna), barley bread (rieska), cheese (juusto), pickled beets (punajuuri), milk, and coffee.

Source: https://en.wikipedia.org/wiki/Finnish_cuisine, http://www.everyculture.com/Cr-Ga/Finland.html