But what about the healthy eaters? For a calorie-conscious nation, the mere sight of a chocolate cake recipe can threaten to take up a whole month's worth of calories on the Weight Watchers chart.

There is an unlikely answer, however. A report this week revealed that dark chocolate actually boosts athletic fitness in the same way as exercise. Combining a small amount with routine exercise could actually enhance performance as much as 50%.

The magical plant compound epicatechin, found in dark chocolate, appears to arouse muscle growth in the same way that a few laps around the park or a workout at the gym would.

Even the most driven and persistent dieter can still have the occasional chocolate craving, and what better way to supplement an active exercise regime than with a bit of dark chocolate indulgence? 

For inspiration, take a look at Waitrose's Californian Chocolate Cake recipe, which includes 175g of dark continental chocolate - it might just give you the incentive to tackle the treadmill.