I had done LL before and have found no difference in energy levels on Exante - as Starlight says, the calories are actually slightly higher, and because you're in ketosis, your body isn't looking for those fixes of calories in the same way.
If you like having 4 packs, you can always split one of the Exante packs, some people have the bar in two halves, or you could do the same with one of the shakes or soups.