The UK is in the midst of a diabetes "crisis" and the prevalence of fried chicken shops is not helping, a leading GP has suggested.
About four million British people are living with a form of diabetes, twice the number from the early 1990s, a UCL report said.
That represents seven per cent of the population, while a further half a million are estimated to be living with undiagnosed diabetes, researchers said.
Sir Sam Everington, who leads a south London general practice, said obesity, diet and lifestyle factors played a role in the rise, especially in more disadvantaged areas.
"Every Tube stop you go out from (the City) towards east London, you lose a year of your life," he told a press conference on Thursday.
Sir Sam highlighted the borough of Tower Hamlets, saying life expectancy and quality of life were significantly lower than central London.
But he said it was dangerous to denigrate people for being overweight as if it were a moral choice, because risk factors can be hard to avoid.
"In Tower Hamlets there are 42 chicken shops per secondary school," he said. "So to assume that a child who is obese is at the same risk (as another) is entirely wrong.
"You actually have to drive out inequalities ... and that's quite a challenging concept."
The GP said there was "nothing wrong with the occasional chicken and chips" but it was problematic if such meals were the norm.
"If people are eating that, they're not having as much fruit and vegetables."
Sir Sam said cutting down on meat was beneficial, hailing the release of the new vegan sausage roll by bakery chain Greggs as progress.
"Which actually they can't produce enough of. They're in trouble because they've launched it and they can't meet demand," he said.
London pharmacist Imran Khan said community pharmacists could help to ease the pressure on GPs who are seeing a "tsunami" of diabetes patients seeking help.
He said they could help with performing tests and providing treatment but they are restricted in what they can do.
"We're missing a major opportunity," he said.
"Community pharmacists are uniquely placed. They have access everywhere. It's a tsunami out there.
"If they need a little bit of extra training, fine. Get them to the level. We could have somebody having insulin titration within a week. Not 16 weeks."
Professor David Taylor - who authored UCL's report Overcoming Diabetes, released on Friday - suggested the NHS should provide more funding for blood tests.
"Arguably, everyone over 40 should know their HbA1c number, which averages blood sugar levels over three months," he said.
Diabetes UK's director of research Elizabeth Robertson labelled the "complicated" disease a health "crisis".
"It's about the individual person who is experiencing this condition," she said.
"We really need to start to treat, diagnose, prevent, care for and manage people in a very personalised way."
Dr Robertson said community-wide education about the effect of fat in the liver and pancreas was crucial for the treatment of Type 2 diabetes.
Recent research has found weight loss can not only prevent Type 2 diabetes, but actually put it into remission in many cases, she said.
She said the UK had "world-leading" diabetes research and innovation and a strong NHS system, but more investment and teamwork was needed to make the most of them.
The report said if authorities, politicians, doctors and patients work together then diabetes could be "effectively overcome as a major health hazard by the 2050s".