Antwerpen is a city in Belgium.
Dumpster diving and free stuff
The grocery chain Delhaize has awesome dumpsters with bread, fruit, vegetables, meat, coffeecakes, dairy products and whatever you can imagine (around Christmas you could even find live lobsters). Most of the stores on the outside of the ring road close at 20:00 and all their containers are good.
Update 11/2016: Unfortunately, Delhaize placed 3 meter high fences around the dumpsters at Delhaize Wilrijk. The dumpsters in Hoboken stand also behind a closed gate. This makes it impossible to dive there.
Here is the list of all markets in Antwerpen:
If you come at the very end of the market, you might score some free vegetables and such as lefovers from sale.
Trying to find free food at Sint Jans market might most likely be a complete waste of time. There are only a couple of vegetable stands and the Flemish vendors there are bitter and mean.