And there's the rub. Coconut's purported health benefits range from fighting infection and aiding weight loss to curing dementia and cancer. Some websites claim coconut water can be injected to fight dehydration (nope, sorry), while Paltrow even cleans her teeth with the oil.

But are any of the health claims true? The evidence is sparse, according to food scientists. Coconut oil is almost pure saturated fat, a much more concentrated source than either butter or lard. While saturated fat is no longer the dietary demon we once thought it was, coconut oil is no health food and should be consumed in moderation.

"There is nothing special about coconut fat and it should be treated like all other saturated fats when consumed in the diet," says Dr Scott Harding, lecturer in diabetes and nutritional science at King's College London. "From a strictly cooking perspective, as long as total calorie intake is healthy and people are eating a balanced diet with good variety, there is no reason to fear any cooking fat or oil."

Coconut water, the juice inside young coconuts, has also been hyped as a miracle drink. But again, experts say there's no evidence to support the health claims.

"Coconut water does contain electrolytes like potassium and magnesium that are quite good if you have been sweating," says Sophie Claessens, registered dietitian and spokesman for the British Dietetic Association. "But you could achieve the same thing or better with a banana or piece of peanut butter toast and a glass of water, milk or juice. Coconut water is expensive and unnecessary, so I don't recommend using it."

One question mark hanging over the coconut craze is: can coconut supplies keep up? Possibly not, as tree numbers are falling due to old age, disease and bad weather. "Governments of coconut-producing countries would need to step up the support provided to growers to ensure that the booming demand does not have irreversible consequences on the environment and place unrealistic and risky demands on family-based farms," says Tim Aldred, the Fairtrade Foundation's head of policy and research. Consumers should buy Fairtrade so farmers can reinvest the extra money they earn on sustainable farming practices, he says.

Lucy Bee, co-founder of the Lucy Bee coconut oil brand and author of new cookbook Coconut Oil, Nature's Perfect Ingredient, agrees. "I've come to realise that the question is not so much 'What does Fairtrade do?' but more 'Do you know how products are produced if you don't buy Fairtrade?'", she says. "Our products are certified by the Fair Trade Sustainability Alliance and they ensure that those that produce our coconut oil directly benefit. For only a few pence more in cost to us, we can all make a huge difference to the lives of those in our producer communities." It's something worth considering in the supermarket aisle. Or we might find the wheels fall off the coconut bandwagon.