Being too fat could be one of the main risk factors for long Covid, British scientists believe.
They have launched a trial to investigate whether losing weight can ease symptoms of the poorly-understood condition in overweight and obese people.
Glasgow University researchers will recruit 200 Britons who have survived Covid but are debilitated by lingering symptoms months later.
Half will be put on strict 850 calorie soup and shake diets, and the rest will carry on with their normal meals and attend long Covid clinics.
The groups’ symptoms, weight and quality of life are to be monitored for six months and compared, before the remaining patients are added to the weight loss scheme.
Previous research has shown infected people with too much body fat are more likely to suffer long Covid, as well as being at higher risk of serious illness from the virus itself.
Obese people often have underlying health woes such as high blood pressure and inflammation, which make them more vulnerable to infectious diseases.
More than two million Britons say they are suffering from long Covid, which sparks debilitating symptoms including breathlessness, fatigue and ‘brain fog’.
Many sufferers are left fighting the condition for around 12 weeks, but some can still experience Covid symptoms a year after fighting off the infection.
Long Covid strikes down at least one in ten people who catch the virus, including young people who are far less likely to become severely ill from Covid itself.
No universal treatment exists for long Covid — but the NHS has opened up dozens of clinics across the country to help sufferers and give them personalised care plans.
The University of Glasgow study has been named the Remote Diet Intervention to REduce long Covid Symptoms Trial — or ReDIRECT.
Participants will follow the ‘Counterweight’ diet which is being prescribed by GPs in England to tackle diabetes.
It sees patients put on a liquid diet of four shakes and soups a day, a total of 825 to 853 calories depending on the flavours they choose.
Once they lose enough weight they will be moved onto a plant and meat based diet with lots of fresh ingredients.
Patients will be able to follow the programme remotely from home.
Dr David Blane, clinical research fellow in general practice and primary care at Glasgow University said: ‘We’re delighted to be doing this research, working closely with people affected by long Covid.
‘We know that people with long Covid are frustrated by the lack of treatment and support options currently available.’
Study co-author Dr Emilie Combet said: ‘People with long Covid have overweight/obesity to a similar extent than the rest of the population, which may worsen their symptoms.’
Scientists are not sure what exactly is causing long Covid, but it is thought damage done to key organs such as the lungs by the virus may be part of the problem.
They have raised concerns that cases of the condition will accelerate in the coming weeks as the virus is allowed to run rampant through the population.
It comes after an Imperial College London survey of 500,000 participants found a third of patients reported at least one lingering Covid symptom 12 weeks after the initial illness.
The most commonly reported symptoms included tiredness, shortness of breath, muscle aches and difficulty breathing.
Broadening their results to the wider population, the researchers estimated that two million people — or one in 30 — will have suffered from long Covid months after clearing the disease.
They said an even greater amount struggle with debilitating symptoms for several weeks after their coronavirus infection.
Imperial found the risk of developing the poorly understood condition increased as people got older — in line with how the risk of Covid itself rises with age.
Those who suffered a bad bout of Covid and received hospital care were also more likely to suffer long-lasting symptoms.
Imperial said other risk factors included being a smoker or vaper, being overweight and living in deprived areas.
There is currently no medical definition for long Covid, as scientists don’t yet know enough about the condition.
But people with certain symptoms that have been linked to coronavirus that do not get better within a few weeks are defined as having long Covid.