More than one in four adults in the UK are trying to lose weight "most of the time", a survey has found.
Many people are weight conscious
The poll, by analysts Mintel, estimates that this means 13 million people are effectively on a permanent diet.
Almost two in five (37%) women were dieting most of the time, compared to around just one in six (18%) of men.
The research found that although people were conscious of the need to eat well for the sake of their health, many were dieting to look good.
Jenny Catlin, a consumer analyst at Mintel, said: "Many people are now watching their weight because they are more knowledgeable about the effects of their diet on their health and general well-being.
65 and over: 49%
65 and over: 44%
Eating lots of veg:
65 and over: 77%
"But on top of this 'cosmetic' slimming has become big business. Today more and more people are dieting for aesthetic reasons as opposed to health reasons.
"This is often in response to peer and media pressure to achieve a slim and attractive figure."
The survey also found almost one in six (18%) British women often skip meals to keep their weight down, while for men the figure was nearer one in ten (11%).
Young women aged between 15 and 24 years old were the most likely to do this.
Ms Catlin said: "Eating balanced, regular meals seems of little interest to a high number of women.
"The major danger here is that skipping meals in particular is only a short-term solution to losing weight, and is also widely considered to be really very unhealthy."
The research also showed that younger people are less likely to eat healthily - and to be aware of the benefits of healthy eating - than those aged 65 years old and over.
Older people were more likely than teenagers to avoid fats and sugars, eat a lot of vegetables and to chose light food.
Ms Catlin said: "This concentration on eating healthily shows that older generations are prepared to adjust their diets for the long term good of their health.
"Younger people on the other hand want to see fast results and so are more likely to 'binge diet', by skipping meals or trying out new diets."
Sara Stanner, of the British Nutrition Foundation, said it was very difficult to get healthy eating messages over to young people as they paid little concern to the prospect of developing disease decades in the future.
She said it was probably a good thing that large numbers of people were trying to do something about their weight - whatever their motivation.
"There may be a small percentage of people who worry about their weight when they don't need to and run a risk of developing eating disorders," she said.
"But research shows that about half the population is overweight, and so the majority of people who are dieting do probably need to do something about their weight."