This is the skin of a 59-year-old man. He surfed at ten-years to 33 years of age in the hot sun off the island of Oahu, sometimes for six hours at a time. He ate loads of sugar and tons of red meat. He ran, he hiked. He usually had a smoothie of celery, apple, kale, carrots, acai, bananas, and sometimes pea protein as his first meal. Today, he biked to and from Walnut Creek to the end of the Concord Airport (about 20 miles) in the 92-degree-F heat. He tries to run 3 miles at least four times a week. He is a heart patient with five stints. He almost never dons creams. He runs uncovered. He uses no lotions. Simply takes a shower using a body wash and scrubs with a nylon puff mesh.
The point I want to make is the skin is a byproduct of genetics. The more I work out, the more I am attracted to good food. But, the skin is almost unaffected by the consumption of food. I believe that if you put things on your face, at least in my case, it stands the chance of getting in the way. It almost always affects my eyes. Nothing is better than your natural systems. So I agree with you about the internal diet, but I believe that you can create desire for good food by working out. Getting out and doing it activates the endorphins. I literally want to run. I crave it. My back is better, my overall musculature is better. I do feel the affects of sugar. I feel it is very bad for you. It criples drive and exhausts the body.
Again, I believe the overall health of the skin is tied to genetics.