Need some help

As most of you probably already know, Maggie can't have sugar. That is to say, her body just can't process table sugar like the rest of us can. Fructose (fruit sugar) doesn't cause her any problems, but if she eats a high sugar food or eats many low sugar foods, she gets stuffed up, coughing, allergic response, slight swelling in her face, and horrible, BD-type behavior.

She knows this, but she's 7. And impetuous. Three weeks (or so) ago, she snuck high sugar foods and, as a result, coughed day and night for week, had troubles at school and home, was stuffed up, tired, achy. It wore off in about a week. Two weeks ago, she did it again, with the same result. You'd think she'd learn, right?

Tonight, I caught her mid-sneak. It was just peanut butter, which I don't restrict much. But going at a jar of peanut butter, with a spoon, in the dark, when you are supposed to be in bed, and jumping when she got "caught", means she at least thought it was a taboo food.

And this, just minutes after talking to her about Valentine's Day and how she absolutely must not eat the candy at school and MUST bring it home to exchange with some of her favorite, non-sugary treats and her promising. But now, I don't know if I trust her to not sneak it at school or on the bus or both.

So what do I do? What would you do? Let her try to do the right thing and try to trust her to not eat the candy? Risk her shocking her body into sickness again, at the risk of having to up her asthma medication? Treat her with prophylactic allergy meds just in case, even if they "dope" her up? Restrict her from even attending the Valentine's Day party? Ask the teacher to take away all Maggie's Valentine's and have Jay or I stop by the school to pick them up, so she can get the cards but not the candy?

Seriously, I need some advice here. What would you do? And how else can we get it across the Mags that, for her, sugar is toxic... at least for now.