Mexico’s Manuel Uribe, once the world’s most obese man, is now vying for a different record: the human who has lost the most weight. Uribe, who weighed as much as a small truck at more than half a tonne, is dieting while confined to a reinforced bed that he has not left for the past six years because he is so heavy.

He has lost 235kg since March 2006 on a diet of grapefruits, egg-white only omelettes, fish, chicken, vegetables and peanuts.

Now weighing 325kg — the size of three hefty men — Uribe is still unable to move his swollen legs but hopes to get out of the house next month for only the third time in six years to celebrate his 43rd birthday. He will still be in bed, hauled onto a tow truck for a trip to the mountainous countryside outside his home city of Monterrey in northern Mexico. It will be a rerun of a failed attempt in March that was thwarted when his bed hit an overpass.

“It’s a miracle I’ve got this far. I was going to kill myself two years ago when my wife left me, but God sent me excellent doctors,” said Uribe, his torso still huge with flaps of puffy white skin and sagging, fatty bulges. Uribe spent the 1990s eating pizzas and burgers in the US where he worked as a computer repairman. Addicted to junk food, he eventually tipped the scales at 560kg back in Mexico, binging on greasy tacos. His bulk made him the world’s heaviest man and won him a place in the 2008 edition of the Guinness World Records.