If we ask why the need for hydration of our skin we should pause to understand the role of water in our body and need constant moisture of our skin. A bad skin constantly hydrated not only grow old long before other well hydrated but get a significant increase in sensitivity to external agents with consequent irritation or skin prone to allergic processes.
Consequence of this would be our skin to appear dull poor hydration, elasticity and natural shine without (not be confused with the brightness caused by excess fat).
For our skin can be as bad as being malnourished pregnant in excess.
In the first case the so-called expression lines will be felt much more besides roughness and tendency to appear over the formation of wrinkles; however an over-nourished skin will have a greater chance of overproduction of fat with all the inconveniences caused. In both cases food is a key factor in determining whether your skin will be well nourished or not.
As you have seen the struggle to keep skin hydrated and nourished properly not only has to do with our beauty, has much to do with our health. Do not take it lightly.