I think my 4yo daughter's too thin. How do I help her gain weight?

Hello, Firstly being thin doesn't mean she is unhealthy. i have been a thin girl all my life though it is another thing that now I am struggling with my weight. ;p If your girl is active and eating well I do not think you need to worry. Anyway, first identify the reason why she is low in weight. I think, you can give her appetite increasing syrup after consulting with her paediatrician. Here is a link, please go through it, I think it will help you a great deal in adding things to your daughter's diet that can help her gain weight. http://blog.zisboombah.com/2012/04/14/skinny-kids-boost-meals-for-healthy-weight-gain/