'Carb confusion' has led to people failing to lose weight as avoiding carbs is unsustainable, they said.
The comments come after a survey found that more than a third (37 per cent) of dieters have used trendy low-carb diets.
Despite 'bewildering' messages, government guidelines say carbohydrates are needed as part of a health balanced diet for weight loss.
Many have attempted the diets, endorsed by the likes of Gwyneth Paltrow and Kim Kardashian.
Two thirds (66 per cent) of the 2,103 survey respondents have heard that low-carbohydrate diets are better for weight loss.
But following one has proved too difficult, as more than half gave up because they enjoy carbs too much (52 per cent), 46 per cent felt too hungry, and 30 per cent found it boring.
Encouraging people to cut out bread and pasta is 'irresponsible', experts at Slimming World, who commissioned the YouGov research, said.
'There is a deep-seated misconception that people should avoid carbs when they're trying to lose weight,' said Dr Jacquie Lavin, head of nutrition and research at Slimming World.
'Yet the truth is carbs play an important role both in a healthy diet and in sustainable weight loss – and the current carb confusion is fuelling the UK's obesity problem.
'Obesity not only has an impact on our own personal health but puts a massive strain on our National Health Service, which has to deal with a number of obesity-related conditions.'
There is a growing evidence which proves that foods higher in protein and carbohydrates are far more satiating than foods high in fat, the research said.
Eating filling, lower energy dense foods (those foods which have fewer calories per gram), which include carbohydrates such as pasta, rice and potatoes, enables people to consume a large amount of food without consuming too many calories.
Shockingly, when asked if starchy carbohydrates should be the main source of calories in a healthy, balanced diet, in line with current government guidance, 81 per cent of those surveyed thought this was a myth or weren’t certain whether it was a myth or fact.
The weight loss group said it's important to think of long-term solutions that are attainable, rather than short-term fad methods.
Dr Lavin said: 'What people need is help and advice to lose weight and keep it off.
'Advising overweight people to follow low-carbohydrate diets, which we know are unsustainable and potentially cut out a group of foods that are essential for a healthy balanced diet, is irresponsible.
'It sets people up to fail and is likely to leave them struggling with feelings of guilt and low self-esteem as well as potentially regaining the weight they lost.
'If you want to lose weight this New Year, and keep it off, avoid low-carb diets.'
In the obesity crisis, around 58 per cent of women and 68 per cent of men in the UK are overweight or obese.
In the US, the prevalence of obesity was 39.8 per cent in 2015 to 2016.
An estimated £6billion a year is spent by the NHS treating illnesses linked to being overweight and obesity such as cancer, type 2 diabetes and heart disease.
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