That article has been reprinted on several low carb sites, but they don't mention any studies to prove their point, and appears to be just a theory.
But should you falter and leave the diet for an appreciable amount of time — especially long enough to gain all or much of the weight back — the next time around takes more effort, weight loss is slower, and it takes more carb restriction to get results.
Indeed, once an individual has played this hand multiple times, it can take great effort to get the desired results.
What they are hinting at is yo-yo dieting, which is experienced by a lot of dieters, not just those that have tried low carb diets. Many believe that your metabolism changes after you diet and regain, making it harder to lose weight with future efforts.
Some medical sites discuss this and seem to support the idea of yo-yo dieting reducing metabolism. Others, including the National Institutes of Health, say that this is not true.
There could be other things going on. When you go on a carb restricted diet for the first time, you initially lose a lot of water weight. This is why Phase 1 of SBD causes an initial large drop in weight. But if you have been dieting before, you may not have as much water to lose. So maybe your next attempt may seem like it's not working, even if it IS causing fat loss.
That's interesting about leaving Atkins because it was so restrictive. We recently did a survey of several thousand dieters and the Atkins group frequently said the same thing. Most of them left Atkins and moved to South Beach, where you can eat a lot of carbs. But then most of our South Beachers left for WW, lol, since it didn't restrict types of foods in the same way.
So anyway, I wouldn't put any stock in the golden shot theory. If you like the SBD, then stick with it and you'll lose the weight. Good luck