I'm on day 5 of the 30 day shred. It's a good work out, as long as you do it properly and don't cheat. It's similar to body attack or body combat but only 20 minutes of it. It's like circuits, so they do 2 minutes of cardio, 2 minutes of strength, 2 minutes of abs. Examples of exercises on level 1 are jumping jacks, crunches, squats and lunges.
I was achey for a couple of days in my legs but that wore off quickly, so my body seems to be repairing ok. During my first session I was hungry when I started and when I got up from a floor exercise was a little dizzy. I also get really thirsty after doing it. I haven't felt like I'm not eating enough to do it, I think because it's not very long.
I got my DVD off eBay for about £6. I recommend it, it is only 20 minutes a day and done at home so for me it works because I cannot make any excuses like no time...
Jillian Michaels gives a good mix of motivational talk and letting you get on with it, the exercises are fairly simple so once you've seen her and her 2 other gym bunnies do them it's easy to follow. One of the girls does an 'easy' version of the harder exercises so you can follow her until you progress onto the full version.
If you decide to go for it, you'll need a pair of trainers, a sports bra, floor mat and some hand weights. I'm only using 1 kilo as they are all I have at the moment, apart from some 5 kilo ones which are too heavy for me to do some of the exercises.