Middle School Diets

Today I had a 12 year old come into my office with a headache and stomach ache. No fever, no vomiting, no diarrhea. She asked to just rest for 15 minutes. When I asked if she gets headaches frequently at home she said "No but I just started a new lifestyle diet called Keto last week and now I have the Keto flu so I get a lot of headaches." I let her rest for a little bit and return to class. She says her parents know. I feel very uncomfortable. I'm not sure if my thinking is clear because all I can think of is my older sister who has spent the past 15 years struggling with eating disorders. I worry for this young girl starting an extreme diet and what her future relationship with food will be like. I'm all for kids eating healthy, skipping junk food and choosing fruits or vegetables instead, but I'm worried about a 12 year old starting a fad diet. I'll probably discuss with our school counselor later today, but what would you have done or what have you done when someone so young tells you they're on a potentially damaging diet?