Good question. I never read the content because I just followed my nutritionist's instructions. Magic Milk is an extremely dense, protein-rich substance that's twice as high in protein as regular milk. I am generally active and have no comorbidities that I need to worry about regarding salt or sugar, so I just make it and use it in place of regular milk.
However, Milkman is preferred because the flavor of the milk is just enhanced so much. Other members have mentioned using regular nonfat dry milk powder and the protein grams are identical. So it just is a matter of preference.
When Milkman came out in the Sixties, my family of 10 was elated. We'd get 7 gallons of milk from a farm by driving 30 miles to and from on a Monday night. We'd come home and cram those 7 glass jars in the fridge. We'd skim the cream the next day and lots of cooking and baking went on from there. And then we'd go 50/50 with Milkman every time we opened up a new gallon, which was every day, really, but we'd actually make a batch of Milkman to mix with the milk. It didn't come in pouches, so we just measured and made a gallon each time to match the gallon of fresh milk.
Magic Milk is better nutritionally because you don't add water, so you get a more dense serving of protein. We used it with water because we had to stretch 7 gallons of milk to cover the needs of our family of 10, and once Milkman hit the scene, we ditched the Carnation instant milk and used it and man, it was like night and day. We were a very milk-centered family. In the days before Milkman, we actually went to a dairy farm belonging to someone in our church with two of those big milk cans that held about 6-7 gallons and brought them home. We grew our own vegetables, slaughtered our own chickens, raised and butchered one steer every year and used a commercial locker downtown to keep our beef, venison and fish in, which we also hunted and fished for.
Sorry, tangent. I just loved going to the farm and getting that milk in the cool cinderblock building with the stainless steel tank full of milk being swirled around, smelling that way only fresh milk smelled. I remember one night a tiny little green frog was trying to keep from being noticed on that bright white wall. I put him outside, of course.
Use any milk you want to, and you might also want to ask your own nutritionist about it. Milkman is nonfat, but I think it has either a tiny bit of cream or some artificial way to make it taste like that. It doesn't taste like real milk, but I take it camping with me, dry, and mix it with icy water from glacier-fed streams, and it's pretty good.
For anyone still reading (sorry, I got off on a tangent), mix one packet of Milkman with one quart of nonfat milk and blend well. You'll get 16 grams of protein for every cup you use. Substitute it for water when you cook cereals, cream soups, or make pudding. It is a great thing to do post-op, as it really makes certain you get your protein in at a time when you might not feel like eating too much. That protein helps speed healing and building muscle in the early days when you're not 100 percent. But it's also good to continue using after you're healed. It sure worked for me.