Visible crew/equipment: In the closeup of Evie when she is holding a spoon under her eyes, you can see the boom mic reflected in each spoon. (01:04:15)
Visible crew/equipment: When Tracy and Evie are dropped off in Melrose, as Tracy opens her car door you can clearly see the black camera and a man standing behind it, reflected in the wound-down window. (00:17:35)
Visible crew/equipment: As the camera pans toward Luke playing on his pinball machine, the cameraman is clearly visible, reflected in the right side of the machine. (00:47:50)
Answer: I think what started it was her tongue piercing. She didn't want to eat cause it would hurt and her mom would notice.
I think it's a combination of the tongue piercing and Tracy's new rebellious attitude. She wants to be "difficult" by refusing to eat what her mom cooks. Evie, meanwhile, is trying to impress Tracy's family, because she wants to live there for as long as possible. So she eats whatever food Tracy's mom cooks.
Drugs will affect your appetite.