Obesity is rivalling smoking as a cause of cancer, responsible for more cases of bowel, kidney, ovarian and liver cancer than cigarettes, according to the UK’s leading cancer charity.

Smoking is still the biggest cause of cancer, but Cancer Research UK (CRUK) has warned that government action to tackle obesity is vital, because it is a significant factor in 13 different types of cancer. Obese people now outnumber smokers by two to one.

Michelle Mitchell, the charity’s chief executive, said: “As smoking rates fall and obesity rates rise, we can clearly see the impact on a national health crisis when the government puts policies in place – and when it puts its head in the sand.

“Our children could be a smoke-free generation, but we’ve hit a devastating record high for childhood obesity, and now we need urgent government intervention to end the epidemic. They still have a chance to save lives.”

Excess weight causes about 1,900 more cases of bowel cancer than smoking in the UK each year, said CRUK. There are also 1,400 more cases of kidney cancer caused by excess weight than by smoking each year, 460 more ovarian cancers and 180 more cases of liver cancer.

The charity issued its warning as figures were released by Public Health England and the Office for National Statistics showing the decline in smoking in the UK. There has been a big reduction in the overall smoking rate to 14.7% last year, down five percentage points from 2011. Across the UK, 26% of the adult population were classified as obese in 2016, while 40% of men and 30% of women were overweight.

Simon Stevens, the chief executive of NHS England, said: “Although cancer survival is at a record high, this significant progress is in danger of being undone by the fast-growing epidemic of obesity, given excess weight is linked to 13 types of cancer.

“This study is further proof that obesity is the new smoking, and the NHS can’t win the ‘battle against the bulge’ on its own; families, food businesses and government all need to play their part if we’re to avoid copying America’s damaging and costly example.”

Caroline Cerny of the Obesity Health Alliance, a coalition of more than 40 health organisations, said: “The causes of obesity are complex, but we know that the environment we live in plays a huge role, and currently this is heavily skewed towards unhealthy options. This is why we need the government to push on with plans to bring in a 9pm watershed on junk food adverts on TV and online, reduce the amount of unhealthy food promoted in supermarkets, and take sugar out of everyday food and drinks.”

Q&A Why is sugar bad for you? Show Hide Eating too much sugar contributes to people having too many calories during the day, which can lead to weight gain. Being overweight increases the risk of health problems such as heart diseases, type 2 diabetes, and some forms of cancer. Sugar is also one of the main causes of tooth decay. The NHS advises that most adults and children in the UK eat too much of a type of sugar called 'free sugars'. These are the sugars added to food and drinks, found in biscuits, chocolate, breakfast cereals and fizzy drinks. But they are also found naturally in honey and unsweetened fruit juices. The UK government’s recommendation is that these 'free sugars' should not make up more than 5% of the calories you have every day. That is still quite a lot of sugar - it equates to seven sugar cubes worth for an adult. But bear in mind that one can of a fizzy drink can include the equivalent of 9 cubes of sugar. Children under 4 should avoid all sugar-sweetened drinks and food with added 'free sugars' in it. Martin Belam



CRUK agrees with that agenda. “There isn’t a silver bullet to reduce obesity, but the huge fall in smoking over the years – partly thanks to advertising and environmental bans – shows that government-led change works. It was needed to tackle sky-high smoking rates, and now the same is true for obesity,” said Prof Linda Bauld, the charity’s prevention expert.

The British Medical Association said the government was dragging its heels over bringing in measures to curb obesity. “The severity of this problem must not be underestimated. As well as the pressing need to raise public awareness of the worrying link between obesity and multiple types of cancer, we need to see a reversal of the cuts to public health funding so we can prevent children and adults reaching this critical stage. Failure to do so will continue to cost lives,” said the association’s board of science chair, Prof Parveen Kumar.