The majority of obese people who try to shed weight are unsuccessful, a new study suggests.

Just over a quarter of people living with obesity who had attempted to lose weight managed to lose a significant amount year later.

The new study, which is being presented to the European Congress on Obesity in the Netherlands, examined data on adults from the UK, France, Germany, Italy and Spain.

Researchers, led by Dr Marc Evans from University Hospital Cardiff, looked at information on 1,850 obese adults with an average age of 53, of whom 79% said they had attempted weight loss in the last year.

Most (72%) had attempted diets while others had also turned to exercise, had weight loss surgery, tried medication or used apps.

Researchers found that among those who had attempted to lose weight, 73.4% had not achieved “clinically meaningful” weight loss.

Those who had surgery were most likely to have lost weight – with half losing at least 5% of their body weight.

Some 32% of those who used digital health applications lost weight and three in 10 who took part in a weight loss service lost weight.

Meanwhile, 30% of those who had medication or took up exercise lost a clinically meaningful amount of weight.

Only 28% of people who embarked on a calories controlled or restricted diet lost a significant amount of weight.

But they found that people who had tried more than one method of weight loss – for example exercise plus a calorie controlled or restricted diet – were more likely to have achieved weight loss.

Just 22% of those who just attempted one weight loss strategy had shed a significant proportion of body weight compared to 33% who used a combination of weight loss tools.

“Our survey results indicate that while the majority of adults with obesity are actively trying to reduce their weight, using a variety of strategies, most are unsuccessful,” said Dr Evans.

“This underscores the need for increased support and solutions for weight management.

“And while obesity’s impact on health is well known, our finding that a sizeable proportion of adults with obesity appear at elevated risk of hospitalisation or surgery due to multiple underlying illnesses, undoubtedly adds a sense of urgency to tackling Europe’s growing obesity epidemic.”

Meanwhile a separate study published at the conference found that the impact of losing or gaining weight on serious health problems among obese people depends on their starting body mass index (BMI).

The study, led by Professor Kamlesh Khunti from the Diabetes Research Centre at the University of Leicester, examined data on 422,642 adults in the UK with obesity between 2001 and 2010.

The researchers compared how the risk of developing 13 obesity-related complications – including sleep apnoea, high blood pressure, blood clots, heart attacks, asthma and depression – were affected by a change in weight.

Participants were tracked for an average of seven years.

Weight loss appeared to affect patients with lower and higher BMI scores differently.

For heart attack, irregular heart rhythm and heart failure, those with the highest initial BMI (of 50) got the greatest benefit from weight loss.

But for other conditions, losing weight appeared to reap more benefit for people with a BMI of 30.

For example, people with a BMI of 30 who lost around a fifth of their total body weight had a 56% lower risk of developing type 2 diabetes, but the risk only fell by 39% for those who had a BMI of 50.

“If intentional weight loss in people with obesity with a lower BMI of around 30 is particularly beneficial to health, and weight gain potentially harmful, we should focus on treating obesity earlier in the course of the disease,” said Professor Khunti.