It's a viral-sensation oat smoothie that costs pennies to make and promises to help you lose 40lb in two months. Now our experts put so-called OAT-zempic to the test...

Unless you've been living on a desert island, you will have heard of Ozempic, the weight-loss drug hailed as the holy grail for those with type 2 diabetes and now obesity. But have you heard of the latest weight loss trend, oat-zempic?

Somewhat more appealing than a weekly injection with side-effects such as nausea and constipation, oatzempic is the moniker given to a TikTok recipe for a 'miracle' breakfast made up of 240ml water, roughly 45g of oats, a dash of cinnamon and a squeeze of lime, blended together.

No one is drinking this stuff just for fun - it's thin and sour, with a bitty texture - but online devotees of this oat smoothie are claiming that, drunk daily as a 40-day 'challenge', it's as good for weight loss as the Ozempic jab.

'Down 9lb [4kg] in three weeks!' raves one user. 'Almost a week in and down 4lb [1.8kg],' comments another.

While it's not clear precisely where the oatzempic recipe originated, it appears to have gained traction thanks to a TikTok user known as 'The Chorro King' (@fred_ddy92), whose page is dedicated to his long-running weight loss efforts and who has been posting daily videos singing the praises of his 'oatzempic journey'.

TikTok user 'The Chorro King' - demonstrating the recipe - has been posting daily videos about 'oatzempic journey'

The oft-repeated message in social media posts is that this drink could help you lose 40lb [18kg] in as little as two months.

But this sounds unlikely - and possibly risky. NHS guidance, for instance, suggests a safe and sustainable rate of weight loss to be 1-2lb (up to 1kg) a week (or roughly 16lb, or 8kg, in two months).

Yet there is no doubt that more and more people are taking unverified health advice from platforms such as TikTok.

This week a survey of 2,000 people by nutrition tracking app MyFitnessPal found that 61 per cent of respondents are influenced by or frequently adopt nutrition trends they've found on the platform – and 30 per cent had experienced some kind of side-effect from trying a TikTok diet fad.

So is there any link between weight loss from Ozempic and that from an oat-based diet - other than a punny name?

'Ozempic works by mimicking the action of a hormone called GLP-1, which helps regulate blood sugar levels and reduce appetite,' explains London-based GP Dr Chandni Rajani.

To a lesser extent, oats can also reduce hunger. That's because of their fibre content, particularly a type of soluble fibre called beta-glucan.

'This bulks up in the gut, helping us to feel fuller for longer,' says independent dietitian Carrie Ruxton.

She referred to a study in the Journal of Nutrition in 2001 that found eating oats as part of a reduced-calorie diet resulted in a weight loss of around 4kg (nearly 9lb) over eight weeks.

Does this mean oatzempic could be that rare thing - a weight-loss trend that really works?

'Absolutely not,' says Ms Ruxton.

'The amazing results reported by some TikTok followers are probably due to the effects of intermittent fasting and replacing unhealthy foods with the oats drink.'

Looking more closely at the oatzempic reviews and at those who report losing weight while drinking it, the users also reveal that they are doing much more than just adding this oat drink to their diet: they are fasting, restricting calories, and upping their activity levels in much the same way any dieter might do.

The reason this recipe seems to have caught on appears to be mainly down to its clever name, and the simple fact that - like Ozempic making you feel less hungry -  oats can help you to feel full for longer (though through a different mechanism).

'Oats are generally considered a healthy food choice due to their fibre content, but they don't have the same mechanism of action as Ozempic… [though] some individuals may find them helpful as part of a balanced diet for weight management due to their fibre content and potential to reduce cravings,' says Dr Rajani.

'However there is no single food that helps you shed several pounds of weight - the key is that you are in a calorie deficit,' says Ms Ruxton.

This means you are taking in less energy than you are expending, leading your body to burn fat for energy.

Nutritionist Carrie Ruxton says you could get the same effect - if not better - from a bowl of porridge, a glass of orange juice (for the vitamin C) and a handful of berries

'For example, a more recent study in the British Journal of Nutrition in 2010 found that eating oat fibre without the calorie deficit has no effect on weight. There is no such thing as a quick fix.'

So the oats in oatzempic may not directly lead to weight loss, but at least they are not unsafe.

In fact they are nutritious, providing B vitamins - as well as beta-glucan, which is proven to reduce LDL cholesterol, the so-called 'bad' cholesterol that increases the risk of heart disease.

The addition of cinnamon and lime is potentially beneficial, too, though these ingredients are present here in negligible amounts, says Ms Ruxton.

'The lime juice would provide a small amount of vitamin C, which supports normal immune function; while cinnamon is known for anti-inflammatory effects and helping to lower blood sugar - although the dose used in studies is higher, around one or two teaspoons, much more than the "dash" suggested in the recipe.'

You could get the same effect - if not better - from a bowl of porridge, a glass of orange juice (for the vitamin C) and a handful of berries (for the polyphenols otherwise provided by the cinnamon), she adds, and 'it will probably taste a lot nicer too!'