As far as I know, there are two workarounds to get your customers eat at a bakery.
The first is to offer some goodies for free (here in Germany, some bakerys offer free samples for their customers, but normally they're just really small pieces of cake, bread, ...). Sims will grab these and eat them.
The second is to put the coffee object from Get Together on the lot. As with the first method, you will not make money that way.
So both ways are just to add to the illusion, they will not further your business financially.