The first time I was able to get lasting perfect skin was on a ketogenic diet.
Given everything written on this site, and the large number of studies showing that sugar consumption leads to acne, it is not surprising that an extremely low carb diet leads to better skin.
For many reasons, particularly high saturated fat and animal fat intake, a ketogenic diet may not be the healthiest way to live. A reasonable percentage of people eating keto experience high LDL-P, trigylicderides, and other undesirable heart biomarkers. But a ketogenic diet may be the simplest, most straightforward way to clear skin. Once you achieve that, you can roll back to a more balanced, overall healthy diet.
Some keto friendly foods are: macademia nuts, walnuts, coconut oil, olive oil, chicken, steak, ghee, and the other usual suspects. You may notice that they are similar to the “acne friendly” foods you will see written about elsewhere.
If you switch to a ketogenic, be sure to avoid cheese and other dairy products.
If you are on a ketogenic diet, please tell us how it has affected your skin below.