girl sensory paint hands

Some children have Sensory issues which can be causing behavior. To find out- have them evaluated by an Occupational Therapist (OT) at school or outpatient. Sensory behavior may include avoiding certain textures- food, touch, clothes; or sensory seeking like crashing into walls, craving tight hugs, jumping excessively, etc. Children with autism and ADHD often have sensory issues. Some children without any mental health issues have sensory concerns too. 

A "sensory diet" is helpful for kids with sensory needs. This doesn't mean food but rather activities. Consult with your child's OT, PT, special education teacher, etc to make one. Here are some links with more information.