In an editorial in the latest issue, the prestigious journal warns that further inactivity will magnify the consequences of the epidemic.
Commenting on The Health Profile of England 2007 report released last month, the journal calls it "an unflattering account of the nation's health".
It refers to statistics that show obesity has increased 30 percent in women, 40 percent in men, and 50 percent in children in England in the past decade.
As many as 23 percent of adults in England are obese, compared to 12.6 percent in other pre-2004 EU member countries.
Another report released last month estimates that 50 percent of Britain's population could be obese by 2050.
The editorial said: "Berating people to eat less and exercise more is futile when energy-dense foods are cheaper and more readily available than healthier alternatives, and when cities have been designed for cars rather than for recreation.
"More nutritious foods and healthier activities must become so desirable and readily accessible that their uptake is normal, and unhealthy options so inconvenient and unfashionable as to discourage their use."