Women give up diets after an average of five weeks, two days and 43 minutes, according to new research out today.
While one in seven (13 per cent) women in Britain stick to a diet for 13 weeks or more, nearly one in four (19 per cent) succumb to their favourite food cravings after a month.
Perhaps surprisingly, nearly one in ten women (8 per cent) lose the willpower to carry on dieting after just one week and 16 per cent give up after a fortnight.
Women from the East Midlands and the south-east stick longest to a diet at an average of six weeks, while those from the north-west and Northern Ireland will ditch their diets quickest at an average of four weeks.
The research among 1,000 women found that the average age for a first diet is 26 years, but one in three women (33 per cent) started a slimming regime between the ages of 15 and 20.
A typical British woman will go on a diet 2.7 times a year, but more than one in ten (12 per cent) will slim for up to five times in a year.
Women said the most popular reason for losing weight was being shocked at seeing themselves in a photograph or catching a glimpse of themselves in a shop window, the research also revealed a number of bizarre factors which prompt diets.
Some women admitted they embarked on a diet after being asked if they were pregnant, others when they suspected their partner was having an affair or their sex life had dwindled.
Others decided to reduce their weight to get back on to the dating scene after a break-up or after realising they were the fattest person in their office.
Some decided to lose weight before a reunion with old friends, while others, after seeing an unflattering picture of themselves on Facebook.
The study of women's dietary habits was commissioned by sugar substitute brand Splenda, whose Small Steps campaign aims to get people to reduce the amount of sugar in their diets.
Nearly a third of women have actually put weight on during a diet, with the average weight gain 3.9lbs.
Six in ten women (59 per cent) said food cravings make diets difficult, followed by 'simply loving food' (42 per cent) and feeling depressed (30 per cent).
Other factors which make diets difficult include cooking and shopping for the rest of the family, going out to dinner and slimming on your own.
In fact, weight loss is most likely to be derailed by dieters themselves, partners and female friends.
'Some decided to lose weight before a reunion with old friends, while others, after seeing an unflattering picture of themselves on Facebook'
The top five cravings which people find hardest to resist during a diet are chocolate (48 per cent), crisps (31 per cent), cheese (26 per cent), bread (26 per cent) and wine (23 per cent).
But other irresistible treats include biscuits, cakes, sweets and even Indian and Chinese meals.
When it comes to strange things people have done in order to stick to a diet, women admit they have eaten in the garden shed away from their family, eaten food that was going off to lose their appetite, bought clothes which were too small, padlocked cupboard doors and even gone to bed early.
Maria Somalya, a spokesperson for Splenda, said: 'We know that going on a diet can be a challenge for many women. However, the real test of a diet is not just losing a few pounds quickly, but taking small steps in your lifestyle that last for years and can make a big difference.'
source : daily mail