More than 1m prescriptions are made for obesity drugs a year - eight times the number dispensed seven years ago.
The majority of these were for two treatments - sibutramine and orlistat.
Sibutramine works by altering chemical messages to the brain which control feelings about food, while orlistat prevents some fat absorption.
Just 127,000 obesity pills were prescribed in England in 1999, but that rose to 1.06m in 2006, according to the NHS Information Centre.
It comes as figures show that obesity is rising.
Nearly a quarter of adults are obese - up 50% in the last 10 years, while one in six children aged two to 15 are classed as obese - up from one in 10.
The increasing use of obesity drugs is partly driven by the fact that more have come on to the market - orlistat was only licensed in the UK in 1998 and sibutramine in 2001.
But Dr Jim Kennedy, prescribing spokesman for the Royal College of GPs, said the condition was also now being taken more seriously.
"Government, patients and doctors are all more aware of the risks and therefore more willing to discuss obesity.
"This means there is more of a willingness to consider treatment options."
Dr Kennedy said patients would only be prescribed obesity drugs alongside a programme to encourage a healthier lifestyle by altering diet and increasing physical activity.
"Patients would have to demonstrate they are genuinely committed to losing weight and doctors would then only prescribe these drugs if there was a high risk from things such as stroke, diabetes or heart disease."
He also pointed out that the 1m prescriptions a year should be seen in context as there were 13m GP consultations each week.
But Professor Alan Maryon-Davis, president of the Faculty of Public Health, said: "Doctors and other health professionals do not have the time to spend on the in-depth diet and exercise advice that is really needed.
"So my fear is that these drugs of last resort are actually used quite early on. It is too easy to turn to the prescription pad.
The NHS Information Centre also revealed the results of its annual health survey.
More than 21,000 adults and children were quizzed about the food consumption and activity levels.
It showed that the gradual rise in the numbers eating healthily and doing regular exercise was continuing.
But despite the increases less than a third of adults and one in five children eat the recommended five daily portions of fruit and vegetables.
And just 40% of men and 28% of women were taking part in 30 minutes of physical activity each week.
And the survey concluded from the lifestyle habits and the height, weight and waist circumference measurements taken that over one in five people were at risk of cardiovascular disease.
Professor Maryon-Davis said: "These findings are worrying, especially when you consider that it is people from poorer backgrounds are the ones who are struggling most to adopt the healthier lifestyles."