Basically no. The 3 shakes are made specially to keep the body healthy and working. If you reduce the shakes you'll reduce what the body is taking in. Its a definatly a bad idea to not take the recommended 3 shakes.
Iv missed shakes before and my doctor (who i do the diet through) basically said it can hinder the weight loss just like not drinking enough water can. Definatly take the 3 shakes, if you do forget one dont panic but try not to make it a habit as it really doesn't help like you think it would.
dont panic as a one off, we have all (maybe) done it.
But dont do it on a regular basis.
The shakes give you the minimum you need for a days nutrition. Below that your body goes into starvation mode which means it conserve even the most meagre of calories. Even LT!! When you come off LT your body will again conserve! So for the best effect take your 3 shakes a day and drink at least 2l of fluids on top of your shakes!!
I can only echo what Theresa said. The shakes are developed to give you all the vitamins and minerals you need to be/stay healthy so you need to have them all otherwise your body can go into starvation mode and then you won't lose weight.
However missing one won't hurt as long as it is not a regular accurance. We all do it - I often forget my last one and end up having a yummy chocolate one just before bed. A particularly nice way to end the day!
I've been really struggling to get my shakes into me as well actually but am aware I need them all. I've went days with NONE! Which is crazy. Always had me water though. Actually now that i think of it, that could be why my weight loss seems to have stalled since day 5. Missing days has prob sent my body into starvation mode. I need to wise up methinks.