Guess what? Apparently, according to scientists who actually get paid good money to research such outlandish ideas, food is good for us. And get this, some foods are better for us than others. When you've recovered from the shock of that level of insight, it may further surprise you to learn that the foods that are best for us tend to be fruits and vegetables.

But though most of you have known this since your mum first implored you to "eat your greens", it wasn't until Dr Steven Pratt's 2004 book SuperFoods: 14 Foods that Will Change Your Life that we learnt to call such ingredients "superfoods", and, admit it, since then every time you've eaten something that falls into that category you've felt a glow of self-satisfaction and righteousness.

And look at the marketing boost the word has given to a range of edibles from blueberries to spinach to wheatgrass to pomegranates to acai berries. According to Christina Merryfield, the lead dietician at the Cromwell Hospital in London, however, "The term superfood is misleading as there is no clear definition and many of the supposed health claims are vague or not fully substantiated. Some so-called superfoods can be good for you as part of a balanced diet, but giving them such a heroic-sounding name confuses the public and can cause worse diet choices."

Further research shows that 61 per cent of us have actually purchased a specific ingredient because of its superfood label in spite of the fact that the latest tests seem to show that, say, acai berries are no more beneficial than apples.

So for anyone attempting to get through this first month of a new year on the healthy diet tip, here's the good news: you don't have to buy those exotic and overpriced things you don't even know how to pronounce any more. The things you should be putting in your basket are the things you always have: fish, fruit, veg, tea, white meat and beans.

And the better news is that, according to the Oxford English Dictionary, the first known uses of the word superfood were in reference to (in 1915) wine and (in 1949) muffins.