Alice Tan Ridley said that the Precious star's figure runs in the family and has not hindered her career in showbusiness.
"The truth is Gabourey would like to lose some weight but the reality is that she would not have gotten the role of Precious if she had not been heavy," she told RadarOnline.
"As her mum I would like to see my daughter healthy, but if she didn't lose weight that's not a problem either - it runs in our family."
The America's Got Talent hopeful recently blasted Howard Stern for calling Sidibe an "enormous, fat, black chick".
"I'm proud of my daughter no matter what and the truth is that there are all kinds of acting roles for all sorts of people," she said.
> Weight group supports Gabourey Sidibe