Health experts, alongside chef and campaigner Jamie Oliver, have called for the Government to impose a sugar tax on fizzy drinks and ban advertising for junk food on TV before the watershed.
The research has been published just days after a poll revealed 41% of adults in the UK are not aware that being overweight increases the risk of developing cancer.
It is estimated that roughly three in four adults will be overweight or obese by 2035.
These rising rates of obesity could not only lead to 700,000 new cancer cases, but could also result in millions of new cases of type 2 diabetes, coronary heart disease and stroke.
This would cost the NHS an additional £2.5 billion a year by 2035 over and above what is already spent on obesity related disease.
“If governments take children's health more seriously and use education to inspire them, we could have a huge impact on their health and wellbeing," Jamie Oliver said.
Experts have suggested small changes in lifestyle could have a dramatic impact on the growing health threat.
According to research, just a 1% shift in the number of people going from the overweight or obese category to the healthy weight category every year could prevent more than 64,000 cancer cases over the next 20 years.
It could also save the NHS £300 million in 2035 alone.
Obesity affects the poorest in society most, with almost half of women (49%) from the lowest income bracket predicted to be obese by 2035.
Meanwhile overweight children are more likely to develop into obese adults, increasing the risk of cancer and other diseases.
There are 10 types of cancer which have been linked to obesity. These are bowel cancer, breast cancer (particularly in older women), gallbladder cancer, liver cancer, kidney cancer, womb cancer, pancreatic cancer, oesophageal cancer, and aggressive forms of ovarian and prostate cancer.
The report stated that one of the main challenges in reducing obesity is cutting the amount of sugar consumed by children and teenagers.
To tackle the huge national health issue, Cancer Research UK has called on the Government to introduce a 9pm watershed ban on the advertising of junk food on TV.
The charity also want to impose a 20p per litre tax on sugary drinks, as part of a comprehensive children’s obesity strategy.
Jamie Oliver, who is currently petitioning for a UK tax on sugary drinks, said: "Being overweight or obese can cause many diseases including some cancers.
"But I believe we can prevent the rising trend in obesity in the UK and across the world.
"Food education is key here. If governments take children's health more seriously and use education to inspire them we could have a huge impact on their health and wellbeing."
He added: "We’re raising a generation of children in a society where junk food is cheap, widely advertised, and packed full of sugar so it's difficult to teach them how to make healthy choices.
"We need to give these kids a chance to be healthier adults - starting with a tax on sugary drinks to tackle obesity and diet-related disease in young people."
Alison Cox, director of cancer prevention at Cancer Research UK, said: "Obesity will be a huge burden to society and the NHS in the near future. We must act now to combat this threat and we need the Government to restrict the marketing of sugary food to children.
"Kids are bombarded with advertisements for unhealthy food. It’s vital the Government restricts this kind of advertising if we are to give our children the chance for better and healthier lives.
"We need to attack the obesity problem on many fronts and we must act now. Otherwise our children will pay the price and the next generation will have poorer health, face more disease and die earlier."
Paul Lincoln, chief executive officer at the UK Health Forum, added that the report has made a "very clear economic case for why we must act now to turn the rising tide of obesity".
He continued: "The government’s planned childhood obesity strategy is a golden opportunity to tackle the availability, affordability and promotion of unhealthy foods that is driving the current crisis in children’s diets.
"This must become part of a broader national action plan on diet and health for the whole population."
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