People in England have put on almost 1.5 billion pounds1 in weight over the last 20 years, according to the figures.
While the population has increased since the mid 90s, so too have beer bellies and midriffs.
A man's average weight has increased by 12 lbs over the last 20 years. And for women, it's gone up by 10 lbs2.
Alison Cox, director of cancer prevention at Cancer Research UK, said: "This excessive weight is putting the NHS under enormous strain and the health of the nation at risk.
"Being overweight or obese is the second largest preventable cause of cancer after smoking, so it's important that people are given a helping hand to maintain a healthy weight.
"Making small changes in eating, drinking and being physically active that you can stick to in the long term is a good way to reach a healthy weight and stay there.
"And the Government can do more to help us all make healthier choices. The sugar tax is a great start and could prevent millions of cases of obesity. But the Government also needs to protect the next generation from junk food adverts on TV before the 9pm watershed. There's no silver bullet; we need a range of measures that work together to tackle childhood obesity. We have an opportunity to stop this epidemic in its tracks and we need to act now."