After the Bravo reality star posted a photo Tuesday of her family cheering on husband Kroy Bierrman at football practice, some fans commented on how much Ariana, 12, has changed since she first appeared with her mom on The Real Housewives of Atlanta.
But Zolciak-Biermann, 37, couldn't stand the body-shaming scrutiny.
"My sweet, smart, motivated princess @arianabiermann. She has the biggest [heart] and is even more beautiful on the inside and you LOW LIFE a---holes who have the audacity to make your rude comments, 'she finally lost weight 'she finally came into her own' WTF is wrong with you!" she captioned a zoomed in snapshot of Ariana.
"What possesses you to sit behind a computer and write a negative comment?!!!!" she added. "Can you imagine if you took the time to write something positive or nothing at all how wonderful this world would be!!! You leave my baby alone she is a child!!! Got it!!!"
The proud mom has six children: daughters Ariana and Brielle, 18, from a previous relationship and sons KJ, 4m and Kash, almost 3, plus twins Kane and Kaia, 20 months, with Biermann, 29, an Atlanta Falcons defensive end.
Their show Don't Be Tardy returns for season 4 on Aug. 16 at 10 p.m. on Bravo.