What do you think of Low carb?

I often check out a forum for bodyweight exercises because I do a lot of bodyweight exercises as part of my dry land training. Anyway, many people on that board are all into this low carb stuff. I tried it out for 6 months but had the feeling that I don't have enough energy if I don't eat enough complex carbs like grains(pasta, rice, bread etc). Is it just me or do other swimmers experience the same? Just wondering...