Some advice about giving advice

While researching for a paper I'm writing for my graduate design seminar course, I came across an article by Dr. Perri Klass called "The Elephant in the Exam Room." It's not within the scope of my paper topic, but I thought it was too interesting to discard. In the article, Dr. Klass reflects on the difficulty of giving nutrition and lifestyle advice to her patients when she herself is not thin. She raises the question, is it best to get advice from people who...

  • personally understand your struggles because they have a hard time following the same advice?
  • no longer struggle because they've made their own advice work for them?
  • never needed advice in the first place?

Think about it. How would the advice likely differ among these three people? Whose advice would you be most inclined to take to heart?