http://www.scientificamerican.com/article/how-much-of-human-height/
Basically, unless you're a starving child, your height is most likely genetic. I'm always amazed when I see first world adults thinking they're short because they ate too much junk food.
I also don't think anyone who's meant to be 7 feet tall is suddenly 5 feet tall because they didn't get fed well. Take 7'7 Manute Bol for example: very underweight and weak, but since his family was tall, so was he.
