These ladies were always trying to lose weight on TV:

Rhoda Morgenstern Gerard (MTM, Rhoda)
Brenda Morgenstern (Rhoda)
Michelle Nardo (Bob Newhart Show)
DJ Tanner (Full House)
Roseanne Conner (Roseanne)

Any more?

Carrie & Doug Heffernan on The King Of Queens went on several diets trying to shed some pounds. :)

I also thought of Suzanne Sugarbaker, on Designing Women. She was a real grouch when she was dieting. But she was funny too.

Dorothy, Blanche, and Rose on the Golden Girls, they were always trying to lose weight for one reason or another but at the same time they would pig out. LOL. :D

when did D.J. Tanner have troube with Weight

Kirstie Alley (Fat Actress)

Alice Hyatt (Alice)

Interesting topic. Some women had weight issues (they thought they were overweight, and the subject was used on the show), and others were just plain fat and the subject never came up.

when did D.J. Tanner have troube with Weight
There was an episode of Full House where Kimmy was throwing a (co-ed) pool party and DJ was freaking out about having to wear a swimsuit. So DJ goes on a crash diet and passes out at the gym. This episode is called "Shape Up" and aired in the fourth season.

Lisa Whelchel who played Blair on The Facts of Life has had a life long battle with her weight. Though it has never pervented her from being a damn sexy lady. :D

Also on The Facts of Life, Mrs. Garrett was always on a diet or mentioning she need to lose weight, and Sue Ann went on a stavation diet for a boy she never met.

Nell Carter on Gimme a Break struggled with her weight.

Also on The Facts of Life, Mrs. Garrett was always on a diet or mentioning she need to lose weight, and Sue Ann went on a stavation diet for a boy she never met.

I remember a couple of season when Charlotte Rae lost weight and her screen appearance looked great.

Alice Hyatt (Alice)

I found that funny in the episode dealing with the Indian when she was a grump over a diet. It was only one episode where she mentioned throughout the series of losing weight. I don't know why they would make Linda Lavin's character needing to lose a few where she was a well built actress. The episode where she was moonlighting for a singing telegram company and Linda have great legs especially in her tap dancing numbers she did.

I remember a couple of season when Charlotte Rae lost weight and her screen appearance looked great.
I remember now, she did lose a lot of weight. Was it after the Eastland years? I can't recall when.

I think they did a Diet episode