Hi toothgap, I haven't heard that one. The good thing, if it happens it's only water (not fat) and your body will get rid of that quickly when your on this diet. The only reason I can think that it would make you retain it , is if you were dehydrated to begin with. If you're thirsty your body is sending you a strong message.- drink or I'm not going to work properly. I do know that when I drink coffee or tea that they are both strong duiretics for me. But that can be a double edged sworded. The more you drink the thirstier you get and the caffine will increase your insulin production.(makes me stall)
I know a little long winded, I guess in short if it's water retention then that can be cured quickly, the more you put in your body the faster it will leave it.
Hope this helped, it's what works for me.
Jo-Ann