Water helps drop calories:

There are some studies that have been conducted on a how drinking a glass of water before a meal can promote the feeling of fullness. However, it has not been established if these feelings of fullness lead to a reduction in appetite, and even if they do, whether the feelings of fullness last at all.
Constipation can be tackled by drinking more water:
A popular notion holds hat drinking water will help tackle constipation. There is no scientific data in western medicine that proves this.