dangers of fad dieting?

iamthesweenmachine

I have a good friend who has been doing Keto (high fat, low carb diet) for almost 2 weeks. It's working well for her, but today she said she was vomiting and felt foggy. I googled side effects of Keto and I'm now concerned that it might have been a side effect/adverse reaction. she said it was a gastroenteral problem when she went to the doctor this morning. should I say something? I am concerned, but I don't want to pry or make her upset. I don't approve of fad diets, but I don't want to talk her out of it.