Have her write down all that she eats in a week (day by day). And make sure she includes the calories. In order to lose weight, she needs to cut 400 calories from the amount she eats daily. Walking is a really good way to lose weight. You can walk as a family as well. Usually when people are overweight, they lose weight faster than someone who isn't over weight. Also, cut out any other drinks besides water. I hope that this helped. :)