There is "inadequate" provision to treat obese patients in the NHS, a report suggests.
Experts said the healthcare system must adapt to meet the needs of bulging Britain after the new report found that services to manage obesity are "poorly developed".
Even though the rate of obesity in the UK is among the highest in the world, the health service's response to the problem is "patchy", according to the Royal College of Physicians (RCP) report.
Too many doctors and nurses are seriously overweight and setting a bad example to the people they are trying to treat, it said.
About a quarter of UK adults are obese and it is estimated that the majority of Britain's population will be obese by 2050. The cost of dealing with the problem has been estimated to be £5 billion every year - a figure which will rise alongside the number of obese Britons.
In many patients, their obesity leads to other complications such as heart disease, diabetes, arthritis, sleep disorders and gynaecological disorders, the authors said. But despite this there are few "joined-up" services for people who are overweight.
The authors recommend a "systematic review" of specialist obesity services. They said that multi-disciplinary teams made up of physicians, surgeons, nurses and other health professionals must be available to cover severe and complex obesity throughout the UK. And there should be a lead physician for obesity at each hospital, they said. They have also called for better training for NHS staff and more research into obesity.
Professor John Wass, academic vice-president of the RCP, said: "Britain is getting bigger and whilst we try to prevent the increase in obesity, we must also prepare the NHS for the influx of patients presenting with severe complex obesity. A patient may arrive at my hospital with coronary heart disease, but if the root cause of their condition is obesity, we must be equipped to deal with that root cause."
A Department of Health spokeswoman said: "We are committed to tackling obesity and are taking action to help people keep a healthy weight and prevent them needing hospital care for obesity-related conditions. The medical profession has a key role in providing advice and treatment to people who are overweight or obese and the Royal College of Physicians can help its members do this.
"The NHS has a range of programmes in place to encourage weight loss. Surgery should only be considered as a last resort and decisions must be clinically-led."