With his portly belly and a fondness for a brandy-fuelled spin on the sleigh, Santa Claus is hardly the picture of health or safety.

Now his wild ways are catching up with him, with calls for a radical overhaul of his bad boy image. A study by Monash University public health expert Dr. Nathan Grills found Santa could be promoting obesity and speeding — and damaging millions of lives.

The childhood legend should be used to promote a healthy lifestyle, the study, published in the British Medical Journal, found.

It suggested Santa slim down by ditching the cookies, mince pies and milk, and snack instead on his reindeers' carrots and celery sticks. His reckless behavior could also encourage extreme sports such as roof surfing and chimney jumping — not to mention speeding.

At the very least he should buckle up or don a helmet, the study says.

"I wouldn't go as far as saying that Santa causes obesity — it's more about raising wider issues around advertising and public health," he said.

A study of American school kids shows Santa Claus is the only fictional character more highly recognized than Ronald McDonald.

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