Somebody commented that one of my kids look thin. I've always thought as long as my kids aren't sickly, all's well even if they may fall a little behind the ideal weight for their age at times. Do I need to step it up a notch and make sure they not only are not sickly, but don't look sickly as well?

How old are your kids? And are the rest of your family generally thin? If that's the case, it could be genetics and there's not much you can do about it. If your kids are happy, healthy then you shouldn't worry. I was underweight for most of my childhood and because I was quite tall, I looked gawky and kindda sickly too but I was perfectly healthy. Also, I was an introvert and didn't really like to go out into the sun so maybe that was the reason why I looked sickly. As long as your child is healthy, happy and generally active, there is nothing to worry about. They are still growing and their bodies still developing.