How do I wean my 15 year old off of gluten-free junk food?

Dear Gluten Dude

Boy did I eat like crap when I was young. My mom changed things up (to my horror) and I cleaned up my diet. Yet when I was diagnosed with celiac disease, for some reason I just had to have gluten-free cookies, cakes, brownies, pizza, etc. I paid the price. Now a mom with a 15 year old who is newly diagnosed with celiac disease is asking how to wean her off the junk food that she has been so used to. Here's her email:
"My 15 year old daughter was just diagnosed and is pissed as all hell and rightfully so. I read your book in two days and loved your voice...I am passing it on to her to read but may cut out the chapters on beer and semen lol. My question is I know you advise to steer clear of gluten free products and I agree but how can I help my pissed off teen who is not a lover of veggies and has allergies to most fruit? My one side of my pantry is currently a gluten free junk heaven!"
Beer and semen? Yikes. I address that, plus the mom's dilemma.