Simple lunch places very close to Lundmarkssalen:
BMC Stamstället (lunch restaurant)
Grönt & Gott (salads)
Ester Mat & Café (vegetarian buffet).
http://www.kc.lu.se/english/employee/service/cafe/
Café Finn Ut (burgers & specials)
http://www.finnut.se/
Café LUX (Lunch restaurant)
http://cafelux.se/
Thai wagon in the Physics department (Thai)
Casual places downtown:
Rå Epok (sustainable sushi)
Taquerian (Mexican street food)
Viggos (every hamburger imaginable)
Mui Gong (authentic Chinese food)
Rauhrackel (Austrian food & beer)
https://www.rauhrackel.se/
Hjulet (à la carte)
https://hjuletmatochvin.gastrogate.com/
Spice & Curry (Indian)
https://www.spiceandcurry.se/
Fancier restaurants:
Saluhallen (various restaurants)
Ved (pizza & à la carte)
Pintxos Gastrobar (tapas)
Italia il Ristorante (Italian)
https://www.italia-ilristorante.com/
Grand Hotel (classical cuisine)
https://www.grandilund.se/en/home.html
Mat & Destillat (modern fine dining)
https://www.matochdestillat.se/
Klostergatans Vin och Delikatess (also fine dining)