nope, same amount of time due to the digestive process. it should take no longer than 3 days to get into lipolysis instead of glucosis as your body's source of fuel.

however...

i too lived off of carbs, and was officially a card-carrying CARB ADDICT. and i can testify that although ketosis begins in three days, and the hunger subsides shortly thereafter, withdrawal from the addiction can take up to a week or two (hence the two-week induction period of super-ultra-strictness). its like being in rehab!