It is said that if you reach for the Moon and miss, you will at least end up among the stars.

And for people hoping to shed the pounds next year, setting out with unrealistic expectations could be the key to losing weight.

A study of 24,000 obese people, who were on a 12 month slimming programme found those who set themselves an ambitious ‘dream weight’ target dropped an average of three stones - around 19 per cent of their body weight.

In contrast, slimmers who set themselves ‘achievable’ goals lost far less.

The study, carried out by the University of Nottingham on behalf of Slimming World, challenges NHS advice that overweight and obese people should aim to lose 5 to 10 per cent of their body weight.

Instead, authors say slimmers planning a New Year purge should ‘shoot for the Moon’ to gain the best results, and are calling for a review of the current guidance.