For the most part we do not place specific eating restrictions on our orthodontic patients. The appliances we make are pretty durable. Most of the restrictions you may place on yourself will be for comfort or convenience.
The primary problem here would be very hard foods that could pop the appliance off the teeth. By very hard I mean things like ice, hazel nuts, jaw breakers, etc. Most foods requiring firm chewing, like meat, are OK. The glue is tough enough to withstand this. Extremely sticky foods like sugar-daddies can also pull braces off or bend wires. Just use a little common sense and discretion, and don't worry about it. If I begin to note an unusual or frequent breakage pattern we can talk about it and then perhaps do some restricting.
Obviously these can be removed during meals so patients can eat anything they want without damaging the appliance. A word of caution is still in order regarding eating habits. We find nearly all appliances are damaged or lost at meal time! When taken out of the mouth at lunch they end up in pockets and book bags where they get smashed. Or they get rolled in a napkin and inadvertantly thrown away. We recommend leaving appliances in the mouth when eating at school or restaurants. It is very difficult to damage them when they are safely snugged up to the teeth. After lunch they can be removed to rinse at the fountain and replace them in your mouth.