I just picked up my prescription today for the XR version and there is a list of side-effects on the paper they give you with it. It says take with or without food and with milk or water. However, after reading that and the product info sheet on the Shire site I’m more freaked out from reading about the sudden death from stroke and heart issues than I am about whether or not it loses effectiveness 
That said the product info sheet says
“Do not take antacids at the same time as ADDERALL XR®.
ADDERALL XR® may interact with a class of medications that reduce the acid produced in the stomach
called Proton Pump Inhibitors, commonly known as PPI (e.g.: Losec®).”
Perhaps the acidic food issue is one of those myths perpetuated in internet forums a result of misunderstanding this caution?
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