Tracey Connelly, 32, has apparently lived off a junk food diet of crisps, cake, and 8 chocolate bars a day since November, gaining two stone in the process.
Connelly was jailed in 2009 after she allowed her son to be tortured by her boyfriend Steven Barker and his paedophile brother, but was released last year.
She begged the NHS for the gastric band operation, that costs £7,000, despite not making efforts to control her diet. She allegedly told neighbours that she wanted to lose weight to get a boyfriend.
The NHS have refused her the surgery because patients must show an effort to lose weight - something which gaining 2 stone does not demonstrate.
Patients must also have a body mass index of over 40 before they can be considered for the surgery.
According to residents at the hostel she is staying at, Connelly spends most of her time in her room, only leaving to buy sweets and snacks at a local shop.
Connelly admitted causing or allowing the death of her son, who passed away in 2007 with 50 separate injuries, including a broken back.
Steven Barker and his brother Jason Owen remain in Prison.