Sophia obsesses over losing one lb and says that she's weighed 99 lbs for every day of her adult life. Later, when Blanche finds out that George fathered a boy by another women, Sophia mentions that she gained 40 lbs while pregnant with Phil.
When Blanche suggests that she weighed 98 lbs. while she was in college, Dorothy asks if she went to the University of Jupiter. Jupiter's gravity is 2.4 times stronger than Earth's, so a person would weigh considerably more on Jupiter, not less.
During the flashback of the all-female gym, Yvonne lists off all that they will need to do aerobics, and leg-warmers was one of them. Dorothy asks her why they need leg-warmers. Yvonne replies, "How else can you keep your thighs warm?" Thighs are from the knees to the hips. Leg-warmers are worn on the calves, not the thighs.
During the flashback where Stan tries to get them to join a self-help group the camera swings toward Rose sitting in the chair closest to the kitchen door and right above her the boom mic is visible.
Later on in the episode Sophia removes her "Double Fudge Amaretto Ricotta Cheesecake" from the oven and places is it directly on the kitchen table with no trivet. Assuming that the cake with baked in a typical 350° oven, the minute she put it down either the tablecloth would've caught fire or, at the very least, started smoking.