Losing weight slashes the risk of developing several chronic health conditions even if people stay obese, research has found.
A major study of more than half a million overweight British adults found that going on a diet has a series of significant health benefits.
Researchers found that losing 13 per cent of your body weight cuts the chance of developing type 2 diabetes by 42 per cent.
It also reduces the chance of going on to develop high blood pressure or sleep apnoea, where your breathing stops and starts as you sleep, by one quarter.
People who lost weight also reduced their risk of getting hip and knee arthritis and high cholesterol by one fifth.
The huge benefits were seen even when people remained obese, with a body mass index (BMI) over 30, after losing weight.
The study, presented yesterday at the European and International Congress on Obesity, was based on GP surgery data for 550,000 UK adults with an average age of 51 gathered over eight years.
Experts said the findings were a ‘wake-up call’ that proves the benefits of even modest weight loss in preventing devastating diseases.
It follows an announcement from the NHS on Monday that thousands of type 2 diabetics will be offered a three-month 800 calorie soup and shake daily diet.
Britain has one of the highest obesity rates in Western Europe, with two in three adults overweight or obese.
Professor Jason Halford, president elect of the European Association for the Study of Obesity which runs the online conference, said: ‘We ignore obesity at our peril.
‘Weight management is clearly one of the best ways to control diseases including diabetes.
‘This study shows the importance of investing in prevention and support to help people lose weight now, rather than waiting for them to turn up in hospital with severe complications ten years down the line.’
The researchers, led by Danish healthcare firm Novo Nordisk, weighed participants four years after their initial measurements were taken, by which time 60,000 had lost at least 10 per cent of their body weight.
The average weight loss in this group was 13 per cent of body weight. Many were still obese, but had lost enough weight for it to have a drastic impact on their health.
The other 492,000 people had not lost weight.
Scientists compared the risk of developing six obesity-related conditions in the two groups.
Study author Dr Christiane Haase said: ‘The difference in the risk of these conditions is striking and indicates that people with obesity could markedly reduce their disease risk through intentional weight loss.’
The research also looked at the impact on heart attack risk, but found no significant reduction.
Professor Nick Finer of Novo Nordisk said: ‘Health policy has been much happier to treat diabetes when it develops rather than the obesity which causes it to develop.
‘That is completely illogical.
‘Now we have evidence that if you lose weight you can prevent these diseases – which are expensive to treat – from developing.
‘It should be a wake-up call to healthcare providers and policymakers.’
Diabetes alone is estimated to cost the NHS £10billion a year.
Professor Finer said of the study’s findings: ‘This is a major health gain that has the potential to add years to your life.
‘We know that obesity is a serious chronic disease, if you have a BMI of 35 or above you are probably losing about seven years of life expectancy.’
Tracy Parker, from the British Heart Foundation, said: ‘To make the healthy choice the easy choice, the Government must urgently put in place the evidence-based measures outlined in its recent obesity strategy, especially a 9pm watershed on TV and online junk food adverts and mandatory calorie labelling.’
Dr Lucy Chambers of Diabetes UK said: ‘We we know losing weight isn’t easy, which is why getting support is important.
‘We need Government to urgently review provision of weight management services and take action to address the barriers to accessing them.’