Scandic Infra City
This is probably the most convenient way to cover your needs for the weekend. The restaurant is located just by the ballroom in the lobby area. Even though it might not be the most financially viable option, it's definitely the closest place to get something to eat and especially suitable in the case of bad weather.
Thai House (Thai, Chinese, Sushi)
The closest restaurant outside of the hotel. Not the fastest service, but the food is pretty descent. You may want to give them a heads up how many guests are coming and an estimated eating time. And be ready to order the check straight after you finished if you want to be on time for any scheduled activities.
Subway (Sandwiches, salads)
Probably the fastest way to get food in the area, depending on how many people are standing in line. Choose your moments wisely! During shorter lunch breaks or straight after workshops, this place tends to get busy. We will be flagging to their staff that our event is happening, but there are no guarantees...
Nonno's (Italian, A la carte)
If you want to have a quiet moment with OK food, this is probably your best shot. Due to the large amount of visitors at the event it could fill up fast. Probably more suited for a longer lunch or an early dinner. Table reservations do occur, but make sure you are there before closing time, due to their strict staff schedule.
ICA (Supermarket)
If you are on a budget, you don't want to rule this option out. Grilled chicken, food buffet (salad options as well), heatable items like noodles, pastas, etc. and obviously yoghurts, bread, cheese, fruit, veggies, milk, juice... Well you get the idea. Other than the content, supermarkets are pretty much the same everywhere.
Max (Hamburgers)
Known for being one of the largest franchising burger joints in Sweden, although a longer walk than the other restaurants, if you are looking for a pretty descent fast food burger it could be worth your trouble. In short, we could summarize it as the Swedish version of McDonalds or Burger King, but better!
Thai Enjoy
Here's a place that we actually have no clue of how the food is, and from the somewhat industrial exterior it doesn't look like much. However, these small joints in Sweden do have a tendency to deliver quality at a descent price. It's a bit of a walk though, but could be a take-away option to enjoy out in the sunny weather.
Mexicana
A restaurant with pizzas and other stuff on the menu. Yet another place we can't vouch for just like the one above, but it does seem to have good ratings on Google and compared to the Thai place that's in the same vicinity, this one at least has a few more seats and can probably offer more variety on the menu.