The 30-year-old refused to stand for the criticism on Instagram after sharing a photo of herself at the Hollywood Beauty Awards in California on Monday, February 18, when she posed for the camera wearing a one-shoulder Michael Kors dress with a ruffled neckline.
While many fans heaped praise on Nina's choice of outfit for the event, others thought it necessary to comment on her slender figure, with one person suggesting the compliments will only make the actress' alleged eating disorder worse.
"I can't believe no one is noticing that shes anorexic (sic)," wrote the follower. "This picture just reminds me of my anorexic self... Nina needs help, you guys are just pushing her to eat air."
Nina didn't take kindly to the unfounded claims, and personally responded on Tuesday.
"Thank you for your concern. I'm sorry to hear you weren't doing well, I hope that you are taking care of yourself and doing better now," she replied. "I'll also let you know that I eat burgers and fries and all kinds of yummy things all the time. You should do the same."
"Eating everything and working out (which I do) is the healthy solution for people who have problems," Nina continued. "Body shaming people on the other hand is NOT healthy and very rude. I don't do that, so you should also do the same. Have a wonderful day."
She also took the time to comment on other unsolicited remarks about her choice of make-up and her age.
Taking another Instagram user to task over claims she was "getting old", Nina fired back, "It's a radical concept called time. I know. Crazy. It's what happens when it goes by. People get older."
"It probably won't happen to you, because you seem to be different than the rest of us. But I'm 30, and damn proud of it! Have a lovely day".
Nina, who hit the age milestone in January, has been candid about her body insecurities in the past, admitting she has "good days and bad days," but tries to remain positive about her health and diet.
"I think being a positive example by practising what I preach hopefully sends out a good message," she told the HuffPost in 2017. "It's about showing people it's not always easy. When you're running around you might be less healthy or have a cheat day, but that's OK because we're all human."