I do agree that especially when you're over 40, you can't lose as easily if you eat too much starch. I think that's why WW worked so well until I turned 40. After that, if I wanted to lose, it had to be more protein and less starch.
Weight loss after 50 seems to be more in fits and starts, rather than a steady descent. That's why I'm going to weigh every week or two, instead of more often. Silly things like being "regular" make such a difference to what the scale says.