I just got braces a couple days ago and am having a lot of trouble eating solid food; I know from tasting them that I enjoy the slimfast shakes, my mom used to drink them, but on the plan it says for you to eat like a sandwich with it. The shakes fill me up and they don't hurt my braces, so is a bad idea to just have the shakes, like one for breakfast, one for lunch and soup for dinner?
Hi, collegegirl. Slim Fast shakes are probably a good idea as the basis of your diet while you get used to your braces and are planning to lose weight. But just the 2 shakes a day plus soup wouldn't be enough calories and wouldn't go along with their weight loss plan, either. Take a look at their website where they show you suggested day's meals for your weight to get an idea of how much they suggest you eat along with the 2 shakes. But notice that it doesn't HAVE to be sandwiches, just healthy choices. I'm a subscriber there, and they have different meal suggestions every day. Some foods that come to my mind that wouldn't hurt your teeth might be jello, puddings, mashed potatoes, creamed vegetables, mashed sweet potatoes, egg salad, tuna salad, grapes, applesauce. Not sure which of those or others you might feel wouldn't bother you, but do try to get some variety! Thank goodness the pain of getting braces is temporary! You'll slowly get used to eating more and more things.
Slimfast
that wouldn't hurt your teeth might be jello, puddings, mashed potatoes, creamed vegetables, mashed sweet potatoes, egg salad, tuna salad, grapes, applesauce. Not sure which of those or others you might feel wouldn't bother you, but do try to get some variety! 
Thank goodness the pain of getting braces is temporary! You'll slowly get used to eating more and more things.