A while ago, I decided to help my daughter keep track of what she was eating by having her take pictures of her meals and snacks. It was an immediate failure: she had no interest in doing it and I kept forgetting to remind her.
I looked up printable food diaries for kids, but they seemed to be geared toward other focuses, rather than our need to correlate consumption to symptoms. Some were pretty, but ultimately not what we needed. It was fairly easy to print up my own, with a space for the date, and then three columns: time, food, and notes. We keep a stack of them in the kitchen, and I try very, very hard to remember to have her fill them out.
We’re not perfect, but getting better and more consistent. This method, low-tech as it is, is more interesting for her than taking the pictures, although I could imagine that a different kid would be bored or overwhelmed by the need to take notes but excited by taking pictures. As I am trying to nail down the correlation between dairy and her anxiety, having good records will, with luck, help me to see what’s going on.