Pica-type behavior w/food items???

My soon to be 7 yo DS has been diagnosed with ADHD but it is controlled by diet (e.g. no food coloring, reduced salicylates). For the last couple months he has been eating food (e.g. yogos, bubble gum, candy) that he finds on the ground. All of the things he goes after have food coloring in them. He also has a tendency to sneak sips from empty soda cans, candy that has been put on top shelves, etc. at home. We have punished him when we catch him and talked to him extensively about this issue. What could be causing this? Is there anything else we can do? His impulse control seems to be a possible issue with this matter.

[althepal39]

It sounds like he just wants candy or sugar.  I've seen kids eat candy off the floor - its gross but it's not that uncommon.  Kids love candy - some more than others.   If he is completely not allowed to have it - it's probably more enticing.