A friend of mine here at work is on the South Beach Diet again, this time doing the induction phase to lose a few pounds. When he's not on this Diet, he eats the Standard American Diet of high carbs, processed vegetable oils, and frankenfoods. I talked to him a bit about eating low carb, carb cravings, and the diet.
He first started the diet a few months ago, when his wife wanted to try the diet and he decided to go on it as well to show his support. The first time he went low carb, he says that he had bad carb cravings for a couple weeks; this time, it took about a week for the cravings to subside.
I remember we were going to a party a few months ago (when he wasn't on the diet) and I stopped by his house before we headed out. We were just getting home from work, having not eaten anything since lunch, and he was famished. He downed a couple tortillas and immediately felt better. This is a strange snack, but it makes sense -- he had carb cravings. He knew what his body wanted. I talked to him about this a bit, and his experience matched mine (before I started low carb): you get to know what your body wants. You have a specific feeling when your blood-sugar is low, it's easy to recognize, and you know that eating bread or pasta will make that bad feeling go away.
His cravings never got too severe; mine didn't either. I never felt grossly sick or insane, but then, I always had fairly easy access to carbs. I had a big problem with 'cheating' when I tried going low-carb a couple years ago. My meals were solid, but then I'd drink a soda or eat chips as a snack, when I was feeling the brunt of carb cravings. He never had that snack habit.
I think anyone on a high-carb diet has constant carb cravings. You're used to it; you feel it constantly. You interpret it as a signal to eat, and it's just a part of life. Only when you decide to stop feeding the carb-hungry beast inside do you really separate out those cravings as something abnormal.
We were both addicted to World of Wacraft for a while, and one of the nice things about an addiction like that is, if you're hungry, it's easy enough to just sit and continue playing instead of getting up to eat. One addiction can help suppress another. (So the lesson is, if you're trying to go low carb and having trouble with carb cravings, pick up another addictive habit, like WoW or gambling or meth.)
He's said the pounds of come off quickly, although he's only barely overweight. He's an ectomorph; he doesn't carry body fat on his face and arms etc, just a bit of extra belly fat. A wheat belly, but not the big beer belly that normally comes to mind. (One incentive to try the diet again, he said, was to fit into his pants and not have to buy new clothes.) The general theory in the low carb community is that you drop weight quickly at first when you start eating low carb, and this is mostly water weight, and then the weight loss slows down. This lost water weight comes from burning off glycogen stores; glycogen being a phosphorylated glucose starch that binds water.
We're both programmers, and that's also something that helps deal with carb cravings a bit. At work, I often get caught up in a problem that occupies my mind for hours. I don't have time to sit and be bored, and think about how hungry I am. This lesson is like the addiction lesson above, but less tongue-in-cheek: if you're doing something that keeps your mind occupied, then you'll be able to burn through time. Once you get past the first one or two weeks of eating low carb, the cravings go away. So the trick is just to survive, and if "time flies when you're having fun" (or mentally occupied, whether it's fun or not) then do something that keeps your mind busy and occupied; something without small breaks.