Naomi Campbell recently revealed that she diets on a cocktail of Maple syrup, cayenne pepper, lemon juice and water.

And the supermodel - who turns 40 later this month - put the results of her incredibly strict regime on show in a striped bikini as she holidayed in Miami yesterday.

She looked trim and lean as she frolicked aboard a luxury yacht with her boyfriend, Russian multi-millionaire Vladislav Doronin.

Price of beauty: Naomi Campbell looked amazing yesterday in a skimpy bikini, which is partly the result of an extreme method known as the Maple Syrup Diet

Naomi famously claimed in 1999 that she 'never diets', but more than a decade on she confessed on Oprah Winfrey's talk show that maintaining her slim frame isn't easy.

She revealed she regularly turns to the extreme Maple Syrup Diet, which involves consuming under 600 calories a day.

'I try to do this three times a year,' she said. 'The most I've ever done it for is 18 days. It's good just to clean out your body once in a while.'

Naomi's devotion to the diet is fully supported by her longterm partner.

Ahoy there! The supermodel was holidaying in Miami with her boyfriend, Russian multi-millionaire Vladislav Doronin

Indeed, Mr Doronin, whom she calls her fitness guru, has been an ally in helping her resist the temptations of food.

'If there is bread on the table, he's like: "Don't eat bread",' she said.

The Maple Syrup Diet is considered one of the most extreme and potentially dangerous weight-loss regimes.

Fans of the diet, which essentially involves consuming only sugary water for days on end, say the combination of maple syrup and cayenne pepper speeds up the metabolism.

Beyonce Knowles and Gwyenth Paltrow are both known to have used the method to quickly shed extra weight.

But the daily intake of under 600 calories - a third of the recommended amount for a woman - means it is low on energy.

The syrupy water is also almost devoid of the protein, fibre, vitamins and minerals needed to keep the mind and body healthy.