What is the difference between a milchig (milk) and a fleischig (meat) Bible study? What major subject areas would you classify as milk? As meat?

The milk doctrines would include those referred to in Hebrews 6:1-3, as well as all of the basic teachings on the principle of the spiritual life. I would say that understanding what one’s position is in the Messiah and what difference that should make in daily living would be among the milk doctrines; therefore, a new believer should be exposed to these things fairly early. Within the milk doctrines, I would also include an overview or overall study of the dispensations and the covenants, as these give the new believer a handle on the Bible as a whole. Once the believer has a good general grasp on these milk issues, he can then deal with the meat, i.e., the specifics of these particular doctrines (dispensations and covenants). One area of meat doctrine specifically labelled as such in Hebrews is the doctrine of Melchizedek and all that it entails. And in general, I would include as meat material those areas of Systematic Theology that go beneath the surface – such as the details of Eschatology, the nature of the God-Man, etc.