That's not ADHD, at least not based on those behaviors. If she has a tendency to chew things she shouldn't and is sensitive to to sounds, touch, odors, and other sensory issues she could be showing sensory-seeking behaviors that indicate something called Sensory Processing Disorder. Crying would be a sign of being distressed over being so overwhelmed with the SPD and any other issues going on IF AND ONLY IF that's what it is.
If she's only eating pizza and french fries, those are very salty foods and depending on where you purchase them or how you prepare them they don't necessarily have much nutritional value... so that can contribute to dehydration.
She needs less salty foods and more healthy foods as well as more water more frequently. She needs more fruits and veggies to help with her hydration. During the summer, grapes and watermelon are fantastic as well as fruit salad made with strawberries and blueberries.
More than anything else you really need to take your daughter to the pediatrician and discuss these issues. Ask your pediatrician to refer you to a specialist that can have her evaluated with a neuro-psych evaluation.