Its far easier for the body to convert carbs to glucose, although it can produce glucose from fat and protein (glucogenesis). The body gets used to getting all its glucose from carbs, particularly on the recommended 230g/day of carbs.
It can take a while for the body to realise that its not getting its ready supply of carbs to make glucose. This is why the first couple of weeks on Atkins is very low carb (20g/day). Its to force the body into a kind of glucogenesis mode.
Once the body is more used to getting less carbs it performs glucogenesis more readily. It will take all the glucose it can from carbs and then work on getting the rest through glucogenesis.
But until it gets used to the idea, its short of energy because its short of glucose. This is why people on the induction stage of atkins can look like death warmed up.
So it should just be a case of getting your body used to it. Consistency is the key, so don't have a carby meal once a day. Just keep a relatively low level of carbs all day and it should get used to the idea. If you were to go very low carb for a few days, it would force the body into that situation, but I wouldn't personally recommend it.
So its pretty much normal initially while you are retraining your body. Depends how quickly you do it. A gradual reduction in carb consumption should not cause the same problem.
And once your body is used to glucogenesis, there is no problem with low energy. Plus of course your trigliceride levels will drop through the floor since the liver has nothing left to make them with - hence the better cholesterol levels with low carb diets.
Personally I prefer an approach based on working out what meals you can eat without sending your BG too high - all down to personal tolerance of the carb type and quantity in specific meals rather than a "low carb" approach. Still, if it works for you then go right ahead. My usual concern with "low carb" is that it can be excessively restrictive and you are going to have to put up with it for the rest of your life. A personalised approach certainly feels less restrictive so may be better psychologically in the long term.