Could you trade hearty meals for low-calorie soups, shakes and counselling sessions? If you’re obese, that’s exactly what you should do, according to experts at the University of Oxford following a weight-loss study.

According to new research published in the BMJ, diet replacement programmes should be recommended by the NHS as a treatment for obesity. Researchers found that participants on low-calorie soups and shakes diets lost, on average, three times more weight than those given standard dietary advice by their GP, as well as reducing their risk of heart disease and type 2 diabetes.

Researchers said that the trial should should provide reassurance about the effectiveness of total diet replacement (TDR) programmes, designed for people with a BMI of more than 30 who struggle to lose weight and keep it off. The diet is not routinely offered on the NHS, and GPs are thought to be wary about advising patients to follow the programme as they do not know enough about it.

The trial took place in 2016 and involved 278 people from 10 GP practices in Oxfordshire. All involved had a BMI (body mass index) of least 30 and, on average, 37.2, while 61% were women and 88% white British. Fifteen percent had diabetes.

Half followed the Cambridge Weight Plan* programme for eight weeks, limiting calorie intake to 810kcal per day and then reintroducing other food gradually over the next four weeks. They also saw a trained counsellor every week for 24 weeks. The other half of participants were given the usual weight management advice and support from their GP practice.

At every stage, people following the TDR programme lost more weight, losing, on average, 1st 9lb (10.7kg) after a year compared with half a stone (3.1kg) for those who didn’t follow the programme. Noticeable improvements in blood pressure and cholesterol levels were also measured in the first group, and those with type 2 diabetes were able to reduce their medication.

The researchers did emphasis, however, that eating habits had to change permanently for the effects to last. Prof Paul Aveyard, study author, GP and professor of behavioural medicine at the University of Oxford, said: "It's boring being on a normal diet and people struggle to stick to it for a year. But these programmes get you when your mental strength is at its highest. You have to concentrate effort into 12 weeks and, because they eat so little, they lose a lot of weight quickly."

Royal College of GPs chair Prof Helen Stokes-Lampard said she would like to see more research in this area. "What works for one patient might not work for another, and GPs will always aim to take into account the physical, psychological and social factors potentially impacting on a patient's health when giving them advice,” she said.

"Ultimately, the best way to stay fit and healthy is to keep active, eat a healthy and balanced diet, get enough sleep, drink moderately in accordance with guidelines, and not smoke."

Last month, the British Heart Foundation warned that five million people in the UK will have diabetes in the next two decades, partly due to increasing obesity levels. Maintaining a healthy weight is one of five lifestyle indicators that can help you lead a healthy life - find out more in our guide. And if you’d like to find out how having the right private medical insurance can help improve your health, read our article on the 12 things you might not know are covered by health insurance!

* The trial was partly funded by Cambridge Weight Plan UK.