Eman Ahmed Abd El Aty had travelled to India earlier this year for bariatric weight loss surgery.
Local media reported that she had lost more than 300kg (660lb) of her 500kg but had died from complications from other health conditions.
A hospital statement said the 37-year-old had heart disease and kidney dysfunction.
"Our prayers and heartfelt condolences go out to her family," said the hospital.
Ms Abd El Aty had been in the UAE capital Abu Dhabi since May after being transferred following specialist surgery in Mumbai, India.
