In Tower Hamlets in London practice sizes have increased by nearly 500 since the beginning of 2013, according to figures obtained by GP magazine.
In Cambridgeshire practice sizes have increased on average by more than 239.
The analysis of figures from the Health and Social Care Information Centre found large increases in numbers in many urban areas together with those on the eastern side of England.
It comes amid a shortage of GPs and a failure to recruit the expected numbers into training.
The figures reflect rising birth rates and immigration into areas seeking low-cost labour.
Dr Michael Parks, secretary of Kent local medical committee, told the magazine that GPs were considering closing their lists.
He said: "It's likely to accelerate and that may become a problem for health services locally in the future, and not just primary care.
"Practices would normally see an increase in their list size as a positive, but I'm not sure they would in the current circumstances."
* In Northern Ireland, GPs were set to present a petition of more than 16,000 signatures to legislators calling for more resources for primary care.
Dr John Kelly, chair of the Royal College of GPs in Northern Ireland, said: “We are approaching a perfect storm in general practice. Funding for general practice has dropped by £21.20million from 2008/09 to 2012/13, a percentage decrease of 8.22%. In the past year alone, GP activity has increased by 7% and this is having a significant impact on patient waiting times.
“The situation looks set to get worse unless the government urgently acts. Northern Ireland already has the lowest GP coverage in the UK at only 6.4 GPs per 10,000 population."
The US study found that yoghurt eaters enjoyed an 18% reduced risk of developing type 2 diabetes <- the kind of diabetes associated with obesity and unhealthy lifestyles>.
The researchers set out to establish whether dairy products could protect against diabetes but found that only yoghurt made any difference.
The findings come from an analysis of the records of nearly 200,000 health workers who have been involved in major studies in the US for periods of up to 40 years.
Some 15,000 people developed type 2 diabetes.
The research, reported in BMC Medicine, was conducted at the Harvard School of Public Health, Boston, Massachusetts, USA.
The researchers say it may be time to conducted randomised studies of the health benefits of yoghurt. Some studies have suggested that the calcium, magnesium and fats in dairy products found in milk may prevent diabetes - but it is also possible that the so-called "probiotic" bacteria in yoghurt improve health.
Researcher Frank Hu said: "We found that higher intake of yoghurt is associated with a reduced risk of type 2 diabetes, whereas other dairy foods and consumption of total dairy did not show this association.
"The consistent findings for yoghurt suggest that it can be incorporated into a healthy dietary pattern."
Dairy consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. BMC Medicine 24 November 2014, 12:215 [abstract]
Deputy Prime Minister Nick Clegg claimed that an extra £1.5 billion would be put into NHS budgets next week in the Chancellor's autumn statement.
The cash would be in line with some of the figures quoted by NHS officials and senior politicians in recent weeks.
It represents about twice the emergency sum - of £700 million - poured into the NHS by the government in an effort to prevent it failing under winter pressures.
Mr Clegg claimed he had made extra cash for the service a central demand in coalition negotiations about the autumn statement and he did not expect "a great political stand-off."
He said the increase would mark a "step change" in funding of the NHS.
But sources close to Chancellor George Osborne, quoted by the Daily Telegraph, claimed Mr Clegg had "never raised the number" in talks - but declined to rule out a cash increase for the service.
The prospects of extra cash - and the coalition row - came as new statistics from NHS England revealed the growing pressure on the service.
In the week ending on November 16, 6,587 patients were kept waiting for periods of 12 hours or more in accident and emergency departments - compared with 2,596 a year ago.
And 7.1% of A&E patients in England have waited for longer than four hours - against a target of 5%.
Representatives of the UK royal colleges revealed they have been considering the ideas from the "Shape of Training" review for the last 12 months.
The proposals were published by a group led by Nottingham University vice-chancellor Professor David Greenaway, commissioned by Health Education England.
They called for big changes in the routes to specialist training, suggesting that most consultants would have more generalist training than at present.
They also suggested that doctors would obtain their full registration from the General Medical Council immediately on graduation from medical school - but might not be guaranteed a training place.
The Academy of Medical Royal Colleges said a steering group earlier this year concluded the proposals would "significantly change" the delivery of post-graduate medical training and education.
It has held six workshops to consider the proposals in details.
A statement from the Academy said: "At its meeting on the 4th November the UK Steering Group reviewed the output from the workshops and considered how this aligned with the recommendations in the Shape of Training Report.
"After discussion, it was agreed that the four Health Departments would present a number of draft policy proposals to the four UK Health Ministers in the next few weeks.
"The UK Steering Group recognises that is for the four UK Health Ministers to decide what the next steps should be and, if policy proposals are approved, economic impact analysis will need to be undertaken to test the affordability of proposals."
The British Medical Association said it was opposed to "shorter, more broad-based" training programmes and is concerned how doctors will acquire the right level of skills.