Hard and sticky foods should be avoided while in orthodontic treatment because these types of foods can break brackets and bend wires. Broken brackets and bent wires will prolong your treatment time.
Foods and drinks that are high in sugar will increase your risk of white spots and cavities while in orthodontic treatment. It is best to avoid these foods altogether. If you decide to eat or drink sugary things, you will need to brush your teeth immediately afterward. If brushing is not possible, then at a very minimum, you should rinse your mouth thoroughly with water.