There are fresh calls for a crackdown on the sale of junk food as research suggests obesity is set to overtake smoking as the biggest preventable cause of cancer among UK women.

Cancer Research UK is urging the Scottish Government to introduce laws to restrict “harmful” supermarket special offers on junk food – a move it says has the backing of 62% of the Scottish public.

A new report by the charity suggests being significantly overweight could overtake smoking as the biggest preventable cause of cancer among women by 2043 – in 25 years’ time – if current trends continue.

Obesity rates among adults are around a fifth (19%) higher now than in the early 2000s, while smoking rates have dropped by a quarter (26%) over the same period, it said.

Being overweight or obese as an adult increases the risk of 13 types of cancer. Some of the most common obesity-related cancers – such as breast and womb cancers – predominantly affect women.

Cancer Research UK prevention expert Professor Linda Bauld said new laws are needed to make food shopping a healthier experience for families.

Prof Bauld said: “It’s positive the Scottish Government has signalled its intention to take action on obesity and will consult on plans to restrict an array of supermarket price promotions.

“Junk food multi-buy offers encourage us to bulk buy and eat large quantities of unhealthy food, the consequences of which have become all too obvious in the nation’s growing waistlines.

“The public wants action and the introduction of laws to curb bargain buys for food and drink high in fat and sugar would be an effective way of helping people make healthier choices.

“The Scottish Government can and must take action – it has a duty of care to protect future generations from the health problems we’re seeing because people are carrying too much weight.”

Public Health Minister Joe FitzPatrick said: “Cancer Research UK’s support for our plans is very welcome as we know that as a nation, we consume too much food and drink with little to no beneficial nutritional value to our diet and contain considerate calories or salt. As this study shows, that has serious implications for the nation’s health.

“This autumn we will consult on world-leading measures to restrict promotions of junk food where they are sold, such as multi-buys, which encourage over-consumption. Consumer spending on price promotions in the UK is the highest in Europe, so it is right we take action.”