A nation suffering from 'fat blindness': Average Briton is only prompted to go on a diet once the scales tip 13st 10lb Many overweight people are suffering from 'fat blindness', say experts Britons are increasingly suffering from 'fat blindness' and are failing to lose weight until they are obese, experts have warned. Only when the scales tip 13st 10lb does the average person decide that enough is enough, new figures show. And seeing unflattering photographs is the first things that stirs us into action. Statistics from Weight Watchers, which records the start weights of all new members - primarily women, but also some men - reveal the average start weight has risen steadily from just over 12 stone in 1989 to 13st 10lb today, an increase of more than 10 per cent. In Body Mass Index (BMI) terms, the average new member's reading has increased from 29.2 to 32. This means that the average new Weight Watchers member, of whom there were more than 850,000 in the UK last year, is now already obese by the time they join. A quarter of the population has a BMI which classifies them as obese (a reading of 30 to 34.9) compared with 11 per cent ten years ago. This steady weight gain over the last 20 years, and our inability to acknowledge when we reach an unhealthy weight, supports the government's findings that obesity is rapidly becoming a primary health and economic threat for our modern society. In fact, over 90 per cent of people in a recent independent study struggled to identify an obese body. Even more alarming is that 68 per cent of obese people questioned didn't even know they were obese. Inspiration: Looking at unflattering photos can be the final straw Alarming figures released yesterday by the NHS Health and Social Care Information Centre show that 65 per cent of men and 58 per cent of women now classed as overweight or obese. Zoe Hellman, Head of Public Health at Weight Watchers said: 'The inability to recognise what an overweight or obese body looks like, is a symptom of how out of touch we are with a healthy weight and shape. 'We're suffering from "fat blindness," which is causing people to delay seeking help until they are significantly overweight. According to Weight Watchers, members top seven triggers for losing weight are: Unflattering photos Poor health Friends or family losing weight Not wanting to be fat for a milestone birthday Wanting to keep up with children or grandchildren Being called names in the street Getting married Where obesity was the exception, sadly it is rapidly becoming the rule. 'It's time to buck the trend. We're here to help people make a positive change in their lives by teaching them to make smarter, better informed food choices for long term, sustainable weight loss. Though losing weight may be daunting, especially for those with a significant amount of weight to lose, dropping just 5-10 per cent of your body weight can significantly improve your health. Ms Hellman added: 'It's natural to judge ourselves based on comparisons of those around us. 'So unfortunately, the more people who are overweight and obese, the more 'normal' it becomes. This phenomenon helps to make being overweight much more acceptable, reducing any pressure to make healthy lifestyle changes or seek support. It may also mean those who are overweight fail to recognise they have a problem with their weight at all.