If you have noticed while peeling an orange, grapefruit, sweet lime etc there is a white thready like substance known as albedo. This has proven to reduce cholesterol levels as it is rich in pectin fiber and also contains polyflavones which are known to reduce cancers. These fibers are also rich in vitamin C.
Leaving the jacket on for potatoes too helps to retain the vitamin C and other minerals it contains. Cooking without skin can cause nutrient losses.
Rather than peeling the skin, It is better to scrub the surfaces of carrots and radish which clean of the dirt plus help to retain the fiber.
Fruits such as apples and pears need not be peeled as they are high in fiber and are great to munch.
Try not to peel the veggies and fruits unless they are tough to digest and so that you reap the benefits of natural fiber.