Ok, I've been testing out my options this week, with the plan of placing an order and starting Medifast properly when I get everything in hand.

However, I've been using a mixture of "over the counter" shakes (Slim Fast, EAS, etc) to just test out whether I can handle the aspartame load and get used to the change from going out to lunch with the group, etc - I know it's not the same as Medifast, but I have had problems with aspartame headaches in the past and wanted to test things out before I commit to the expense.

Anyhow, to get to the point...
I found it worked really well to have the prefab bottles in the fridge, to be able to grab one and go rather than when I had to mix up the powders and try to get all the chunks, etc.

But, now I'm wondering - is there a reason I couldn't do that with the Medifast stuff? Pre-mix everything at home in the morning, even use a mini blender to get it all well mixed, then stash my 4 premade "meals" for the day and grab them as needed?

Is there a concern about nutrient loss after it's been mixed up?

Or is there a chance they get nasty after a while, or anything like that I should know about?

I always drink my shakes right away. I've never let them sit. It should be fine because there isn't dairy or anything that needs to be refrigerated. Soups are even better in a thermos or so I've been told. There are also options that do not need to be mixed such as the bites, crunch bars, and pretzels. And on Medifast you can go out to lunch! You just need to be careful about getting grilled and not fried meats, green veggies, and all in the right amounts. I've even heard of people going to McDonalds and getting a grilled salad for their lean and green. Wendy's has some good salads too though I haven't tried either myself for my lean and green. I'm avoiding eating out until I've been on the plan for a while and can eyeball how much meat is what.

Also, you can order a weeks worth and try it out. It's about $80 for the medifast meals and however much extra you want to spend on your lean and green.

You absolutely can mix up shakes ahead of time! They will thicken up after a couple hours in the fridge, so I prefer to make them in the morning if I'm having a shake at work.

I do the same with soups. I got a Corelle mug with a lid, and mix the soup up in the morning then nuke it at lunchtime.