Dwight C. Lundell, M.D. lost medical license in 2008. Since that time he has been promoting books that clash with established scientific knowledge of heart disease prevention and treatment. His book, The Great Cholesterol Lie, invites people to "forget about everything you have been told about low-fat diets, saturated fats, cholesterol and the causes of heart disease."
That's a nice ad hominem collection there. Not one point I could find about his actual claims. He didn't file his taxes properly? Bad patient review history? These things are not relevant to the scientific claims he puts forth.
Ad hominem isn't always a bad thing. The fact that someone lost their medical license is good information when evaluating professional credibility. Professional credibility is absolutely important when evaluating someone's claims.
http://www.quackwatch.org/11Ind/lundell.html