Her hair turns dark pink.
If it is cloudy for several days in a row, or if Katie doesn't go outside, she drags herself around the house like there are weights attached to her and is more likely to fall over.
On the other hand, after the pink hair incident (of which she aesthetically disapproves) she stops eating for three sunny days and nothing happens except a gradual lightening to blonde. She does drink plenty of water.
Katie decides she wants to be ginger and starts eating a lot of papaya and sweet potatoes and pumpkin and mango and carrots and tangerines and orange bell peppers and cantaloupe and peaches and kumquats and vegan caramels and, of course, oranges. Sometimes she eats red and yellow things, too, but she is careful to balance them out; if she feels like eating something green she covers it in turmeric. The limited variety doesn't seem to do her any more harm than the dearth of two major macronutrients ever did. (She will eat, if encouraged, avocados or tofu, whole peanuts and quinoa - she is not completely void of potential sources of fat and protein - it's just that they seem irrelevant.)
She trips often enough that going around in optimal sun-absorption outfits is kind of a problem: if she scrapes her knee in front of a witness, someone might notice the distinctly unbloody fluid - sap? - that she contains. The compromise is long pants, sleeveless shirts, and light cardigans thrown on if they're going to walk somewhere which she can omit for just lounging on the front steps in the sunshine.
She reads a book about plants. She holds her breath for fifteen minutes before getting distracted and absently starting again. She wonders where she came from and who put her in a basket on Chris's doorstep and why.
She learns to tell people clearly and firmly that she is a "strict vegan". If questioned about her reasons she tells them that she loves animals. Nobody wants her carted off to be researched.
(She is not such a strict vegan as to eschew honey. Honey is fine by her.)
Mercifully, she looks five by the time she is officially five - actually, she looks more appropriate for five than she did for three; she's still slender and oddly-proportioned, but that adds up better for a kindergartener's height than for a toddler's.
She is nervous about going to school and is holding Chris's hand very hard.
"Oh well. Ms. Keenan said," Katie adds, "tomorrow we will have play-doh, but that we were not allowed to eat it. Do people eat it? Is it food?"
"People who aren't plants don't have as clear an idea as you do of what is and isn't food to them," says Chris. "Sometimes children need reminding. I don't think play-doh will do most people a lot of harm if they eat it, but I don't think it'll do them any good either."
"It's really obvious what's food. To me. I don't know by looking whether you or Lizbeth can eat things."
"Other people don't know by looking whether anything is food to them or not. We have to learn how to tell, by hearing about what kinds of things other people eat and how safe or tasty or nutritious they are or aren't."
"It would be convenient. And interesting. But we are mostly good enough at figuring out what is food for us by ourselves, so I don't think it would make a huge difference."