The man named the world's fattest by the "Guinness Book of World Records" credits a low-carb diet for helping him slim down to about 690 pounds, the Daily Mail reports.

At his heaviest, Manuel Uribe weighed almost 1,260 pounds.

The 42-year-old former mechanic was bedridden for six years while stuffing himself with burgers, pizzas and sodas, according to the report.

Once the Mexico native decided to drop weight, he rebuffed doctors' offers to have gastric-bypass surgery, instead shedding almost 600 pounds by following a low-carb regimen, the Mail reported.

Uribe, the subject of a documentary airing Wednesday in the U.K., hopes to slim down to about 265 pounds and is following an even stricter daily diet of fish soup, one grapefruit, half an apple and 18 peanuts, the report says.

One of his nutritionists, Alejandra Garcia, told the Daily Mail, "It's about controlling his hormones. It is not some outlandish fad diet. It is simple common sense refined by science."

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