Recent research with double control groups (real coffee and no coffee) has shown that drinking decafinated coffee increases LDL (bad) cholesterol in the bloodstream while drinking real coffee or no coffee does not.
Researchers suspect the use of robusta beans in decaf rather than the aribica beans used in quality coffee may be the cause. Robusta has more and different fats but more research is needed to find out.
More in Los Angeles Times section F (Health) 11-21-05.