What Causes Whitening Of Skin Under The Nails?

Suddenly all the skin uner my nails on both hands have gotten white and has progressed to the point that now half of the skin appears white or whitish. I feel great but have been dieting ... 2 shakes a days with tons of veggies and vitamins and fruit and ground up walnuts, with a dinner of chicken or beef, and tons of veggies., no pasta or sugar age 73, 5'2 121