Diet has every thing to do with acne.
See these articles:
http://www.nealhendrickson.com/mcdougal ... puacne.htm
In a nutshell, eliminating excess protein, excess fats and dairy products and reducing processed foods and focusing on a nutrient rich diet which all help to reduce IGF, hormones, and inflammation, can all go to helping relieve and or eliminate the problem.
Clin Dermatol. 2008 Jan-Feb;26(1):93-6. Diet and acne.
J Am Acad Dermatol. 2008 May;58(5):787-93. Epub 2008 Jan 14.Milk consumption and acne in teenaged boys.
Dermatol Online J. 2006 May 30;12(4):1.Milk consumption and acne in adolescent girls.