Weight Watchers: 9-Year-Olds Personae Non Gratin

12/22/2010 3:45 PM PST

Weight Watchers: 9-Year-Olds Personae Non Gratin

"Big Love" star Ginnifer Goodwin -- once a 9-year-old Weight Watchers member -- would be unwelcome today, because the diet co. tells TMZ, "Under no circumstances whatsoever" can kids under 10 enroll.

Goodwin claimed yesterday she started WW 23 years ago, back when she was 9 -- but there was a big policy change in 2003 ... The company line now is that it's potentially dangerous for kids under 10 to join the program.

Dr. Suparna Jain -- a pediatric endocrinologist -- tells us WW is wise not to give its stamp of approval to anyone under 10, because the diet does not provide enough calcium and protein for a growing body.  The Weight Watchers program is predicated on calories, fiber and fat, not fundamental nutrients.

WW puts the onus on a child's doctor, saying,  "Between the 10th and 17th birthday, a doctor's permission note is needed and the doctor is responsible for recommending a healthy weight goal."