Who knows what constitutes a healthy diet any more? The backlash against carbohydrates – and the growing consensus that butter, cheese and eggs might not be so bad for us after all – represents a dramatic departure from the low-fat doctrine of recent decades. Barely a day goes by without new headlines trumpeting the miraculous powers of some food or drink (chocolate, for instance, or red wine), frequently followed by others saying precisely the opposite.  Manufacturers, the advertising industry and the media have long indulged our appetite for "wonder foods". Remember the one about Coke curing impotence? Or sugar as a diet aid? No? For your benefit, then, here is a round-up of some of the most outlandish claims made over the years – a suggestion, perhaps, that today's health headlines may best be taken with a pinch of (low-sodium) salt.  Fizzy drinks might now be considered the root of all evil, but when Coca-Cola was created by American pharmacist John Pemberton in the late 19th century, it was said to cure morphine addiction, dyspepsia, headaches – even impotence. Cola, wrote Pemberton, was "a most wonderful invigorator of sexual organs". Adverts described it as the "ideal brain tonic". It is fairly well-known now, of course, that drinkers may have felt a certain buzz, as the cola leaf used in early versions yielded traces of cocaine, which weren't eliminated until the turn of the century.  When this famous ad was introduced in 1931, it was reported that enjoying a pint of stout a day promoted strength, aided digestion and relieved sleeplessness. Since Guinness contains iron, it was fed to post-operative patients, blood donors and, on occasion, pregnant women. In fact, while Guinness is high in flavonoids, which can reduce the risk of heart attack from blood clotting, the iron content is relatively low. You'd have to drink a reported three pints to get the same amount provided by an egg yolk.  Often wrongly attributed to racing commentator and ad man Murray Walker, the original "A Mars a day …" slogan was first used in the UK in 1960, appearing in print well into the 90s. With 229 calories and 30.4g of sugar a bar, it is hard to imagine the ad getting past health authorities today. A modified version of the slogan – "Work, rest, play" – was introduced in 2008.  In the 50s, America's Sugar Association took out a series of ads arguing that sugar could help dieters lose weight. How? By sating the appetite "faster that any other food" and keeping diners "satisfied on less". Today's research suggests precisely the opposite: in the form of fructose, sugar may actually stimulate the appetite.  Digestive biscuits may once have been thought to aid the breakdown of food thanks to their high baking soda content – but that's nothing compared to the claims made about the graham cracker. The American campfire favourite was a key component of the "purifying" vegetarian regime devised by Presbyterian minister Reverend Sylvester Graham in 1829, which he said could put an end to masturbation and other carnal urges. Similar powers were associated with an early incarnation of cornflakes, created in 1894 by devoted Grahamite John Harvey Kellogg (and his brother Will Keith) to be served to patients at Michigan's Battle Creek sanatorium.  Buckfast's origins are considerably more wholesome than its current association with crime in Strathclyde suggests. Created in the 1890s by monks at Buckfast Abbey, by the 1920s it was being marketed with the slogan: "three small glasses a day, for good health and lively blood". Some ads said it "soothed depression", an assertion shared by other tonic wines, including Dubonnet and Sanatogen. While the latter's 1970s slogan, "You feel better after the first glass", probably contained a grain of truth – it is 15% alcohol – today's bottles are sold alongside the stern warning: "'Tonic wine' does not imply health-giving or medicinal properties."  Eggs, chicken, salmon – all fantastic sources of protein. But a Big Mac, milkshake and fries? Yes, according to this Australian ad, apparently from the 80s. A similar campaign claimed that "not only are McDonald's meals good to eat, they're good for you". Judging by this advice given to the company's own employees late last year, their definition of "good for you" has changed somewhat.  Want to live longer? Then buy some pomegranate juice. That appeared to be the implication of POM Wonderful's notorious 'Cheat Death' campaign. The Advertising Standards Authority duly slapped it down.  Today, you can buy "low-calorie" Skinny Water at supermarkets – a confusing prospect for those of us who thought all water was calorie-free– and, until a few years ago, sugar-laden breakfast cereals were being sold as a way to improve attentiveness and bolster the immune system. All of which goes to show that miracle claims are far from a thing of the past.
Alice-Azania Jarvis: In years gone by, the public was told that Coca-Cola cures impotence, biscuits prevent masturbation and pomegranate juice helps you cheat death