With lingual braces, just like with traditional braces, you should steer clear of foods that are chewy, sticky, and high in sugar. These can cause damage to your braces, leading to the brackets popping off and lengthening the overall duration of your treatment.
You should stick to soft foods for the first two weeks after getting braces because the pressure on your gums and teeth can cause discomfort. You should be alright eating things like bread, eggs, meat, cheese, yogurt, soft fruits, etc.