The way I understand it, the essential ingredients are Flax Seed Oil (cold pressed) and Low Fat Cottage Cheese. The oil provides Omega 3 fattie acids and blending it with CC , makes the Omega 3 soluble (it can now readily be assimilated into the cell walls) the Budwig Diet limits all the other fats and oils, so the good oils will be more readily received by the cells.
It taste bad so that's why the fruit etc. I don't know about the fish oil.
The FSO will go rancid very rapidly so you have to mix it as you use it.
Cancer cells, the way I understand it, often begin because the normal cell uses processed oils, that have closely bonded molecules for longer shelf life, in the cell wall and the cell wall, because of the closely bonded molecules, now resists the natural inflow of nutrients and resists the outflow of waste. The now abnormal cell begins to create an anaerobic and acid environment and now depends on glucose (sugar) for fuel. This abnormal cell now reproduces and you end up with cancer.
Sound clear as mud? Picture a window screen, that's how the norman cell wall should work..oxygen and nutrients pass threw and waste products pass out. Now picture a screen window that has a very small mesh.... so small that nothing can pass: that's what happens to the cell wall of some cancer cells. The Budwig drink, in very simplistic terms, replaces the small mesh with normal sized mesh and the cell can breath again.
You know the burning in your mussels after you work very hard? That is caused by acid in the mussel. There is a very complicated process that your body undergoes, involving your inhaling oxygen and exhaling CO2, that eventually will neutralize the acid. I have drunk the Budwig Drink and the burning went away very fast, I have tried it other times and it didn't seem to help... maybe I didn't drink it soon enough, I don't know.
The information on this link seems to agree with the majority of information I have read.
http://www.healingcancernaturally.com/budwig_protocol.html