Hi Stickytape
The nutrition is made up of the 4 foodpacks, you can have 1 bar a day (none in the first week) and the packs are either soups or shakes. I have gone with all soups and the peanut bar (the only one without hydrogenated fat in it!)as I don't like artificial sweeteners/too much sugar either, the mushroom and the chicken are my faves.
Each soup/shake is 125 calories, so you are only on 500 cals a day - if you were trying to replicate this with fish/lean meat/veg, you might find yourself going hungry? Not having done it that way, I don't know...
Looking at the back of a pack, the main ingredient is skimmed milk powder, followed by maltodextrin (glue, basically!) soy protein isolate, soy flour, milk protein, soya lecithin, inulin, flavouring, wheat & maize protein, xanthan gum (another thickener) and then a huge long mineral/vitamin mix - if you have your four a day you have complete nutritional balance (all RDAs met).
The soy protein isolate, xanthan, maltodextrin and proteins are what stop you from feeling hungry, imho - after the first 2 days, I honestly haven't felt the need to eat (although DH has had hunger pangs throughout and has eaten cheese to combat them - he has still lost shedloads, though, but then men always do ).
If you stick to it, it WILL work, but I've been surprised at the number of people in our group who have dropped out/slipped up and eaten. I'll be the first to admit I have no willpower, but to pay £66 a week (c.£800 if you tot it up over the 100 days) to me is a great incentiviser!!
Good luck if you decide to do it - I'm so glad I did... although it is annoying to get my size 14's down out of the loft and find I've sailed straight past them in the space of a week - thank God for Primark or I'd be naked!!