In August, King Abdullah had ordered Khalid bin Mohsen Shaari, who then weighed 610 kg, to undergo treatment in the capital, Riyadh.
His transfer required a special bed constructed in the United States and a forklift to ferry him to an ambulance and finally to a Saudi Air Force plane to a hospital in Riyadh for treatment.
Shaari, who is between 18 and 20 years old, comes from the Southern province of Jazan, was unable to move by himself.
"The patient is responding well to treatment and is continuing to improve, especially the psychological aspect, " Dr Aa'ed al-Qahtani, head of the medical team said.
Shaari's most serious health issues are being managed, including heart and lung problems, diabetes and swelling and lack of mobility in the legs, al-Qahtani said.
Al-Qahtani said that Shaari is scheduled for one more "surgical phase" after which, if successful, he could return to normal life.