not as fast, no - but it's pretty effective.
the differences are that a VLCD is extremely low carb, so you get in ketosis quickly and stay there. this does two things - it stops you feeling hungry, and it forces your body to use fat for fuel more efficiently.
secondly, obviously a VLCD has fewer calories. Loads fewer. If ypou consume say 1000 cals a day, or 1200 - your body has all those calories to burn up first, before it gets to your fat stores. VLCDs typically have around 600 cals a day. You couldn't safely put together your own low carb diet on that few calories - VLCDs are like baby formula in that they're nutritionally complete.
Ultimately, although i'm very happy on a VLCD, I wouldn't and don't go around recommending it. There's no question that it's an extreme thing to do to your body, and if you can make a less extreme diet work for you, then I think you should.
I'm just here after twenty years of trying everything else over and over and hitting a brick wall. Cambridge diet is my last chance saloon.