@aminorharmony asked a few weeks back about foods you can't have after lap band surgery. She is having surgery soon (congrats!) and I was planning on addressing that a while back but didn't get around to it. So, here goes.
When I was pre-op, my doctor and nutritionist went over what foods I should eat, and what foods I shouldn't eat. There wasn't a "can't" in there. They told me that a lot of bandsters can't tolerate certain foods--breads are a common one, foods that are rubbery like eggs are a problem for some, foods that are fibrous like asparagus, celary, or pineapple are another. Basically they told me that it will be trial and error, and you'll know if it's something you shouldn't eat again. Bread is probably the most common problem food, and some people can eat one kind of bread product and not another, others can't have any bread-type food at all, not even tortillas or flatbread. Which is fine, because bread isn't the most nutritious thing you could be eating anyway. Grains are important, but you can get your whole grains in other ways and skip all the carbs in bread.
Personally, I have never found a food that my band wouldn't let me eat. I've never been super tightly filled, either--I think the most I have had is 3.5cc in my 4cc band, and I've never once had reflux or had any food come back up. The tighter the band is adjusted, the more problems you are likely to have with foods that form a gummy ball or aren't chewed well enough. Some people use this to their advantage. The band helps them modify their behavior by not letting them eat certain foods, like bread. But I would offer a caveat to this--the band will never prevent you from eating the real "junk" like ice cream, candy, or most other sweets. Unless you are overfilled, if you can get water down, you can get sweets down. This is one reason that people can be overfilled and still gain weight. They like having their band so tight that it prevents overeating, but they subconsciously alter their diet to include only "soft" foods that go down easily, and just trickle through the banded stomach. This is known as "eating around the band". So, if your band is so tight that you can't eat a good band meal--4-6 oz. solid protein, then a small amount of veggies--but you compensate by eating ice cream and processed junk foods all day, you can take in a lot of calories and get no nutrition. If the tight band causes you to vomit every time you try to eat solid food, or have a lot of acid reflux, you can risk a band slip, as well.
I hope that your nutritionist went over how you should be eating once you are banded, and I hope you've started eating that way before surgery so you know what to do, and can start changing your habits now. A good band meal consists of SOLID food. You should be eating about 1/2 to 1 cup total per meal, and it should consist of solid protein (chicken or meat, fish, etc.) followed by veggies, and if you aren't full/satisfied yet you can have a little starchy food like potatoes. You should not drink while eating, because this can wash food through the banded stomach and cause you to eat more. Your meal should keep you satisfied for 3-4 hours. All of this is once you are past the post-op diet and have had a few fills so that you are starting to experience what bandsters call "restriction".