The 18-year-old singer/actress ended up in a Los Angeles medical center last week...
Now she's revealed it was her diet of chocolate and sweets that left her feeling ill.
She tells Kidd Kraddick's radio show, "I do eat. The problem is I don't eat right. I love everything that's possibly not good for me... I love M&Ms, Kit Kats, Snickers and Goobers at the movies."
Gomez has credited her mum Mandy with helping her improve her eating habits, adding, "She's definitely shoving vitamins down my mouth and following me around. But at the same time, I was a stubborn kid, so I got to eat whatever I wanted. I have to have creamed spinach or cheese on my broccoli. I have to have something that makes it not healthy... (But) I'm good now, thank you. I'm so much better."