I like to walk for exercise, and over the years I have only suffered from chafing on two occasions. In both cases, I realized upon reflection that I had not been eating red meat. As soon as I resumed eating beef, the chafing went away. Also, in both cases, I was getting sufficient, high-quality protein from other sources.
My theory is that the superior quality protein in meat is needed for resilient skin. After all, our ancestors ate meat for thousands of years, so it stands to reason that we may be genetically evolved to require red meat. It is also possible that eating more red meat may help with other skin problems.