please help me find the name of this book

Not my normal content, but when I was in 5th grade I got 2 manga on Easter. One was called hollow fields and The other was this weird story about this girl who eats oats(?) or something like oats but its a small bag of something and she grows up into a grown woman instantly. Like a government corporation was making the oats(??) and they find out she ate them and they kidnap her.  Anyone heard of it?