UK government said in July it is implementing a 9pm watershed for junk food ads.

3.7 million UK kids would see 1.5 fewer fast food ads each day when it's in force.

They would also avoid eating just more than nine calories each day on average.

Researchers used data on children's exposure to ads between 5:30am and 9pm.

The UK government's ban on junk food ads before the 9pm watershed will stop 160,000 children becoming overweight or obese, according to experts.

Children would avoid eating about nine calories a day on average, which would reduce childhood obesity figures by nearly 5 per cent, they claim.

Researchers used data on children's exposure to ads for food and beverages high in fat, sugar and salt (HFSS) between 5:30am and 9pm.

Obese children are about five times more likely to become obese adults with a much higher risk of health problems including cancers, type 2 diabetes and cardiovascular disease

The government announced in July that it would be banning HFSS ads during this period of the day to restrict their exposure to children, but this has not yet come into force.

Junk food adverts during children’s television programmes have been banned since 2007 (pictured, Gary Lineker, who is the face of Walkers)

It's thought that watching unhealthy food advertising increases the calories children eat by triggering cravings and subconsciously directing them to the larder.

Junk food adverts during children’s TV programmes have been banned since 2007, but the government has gone a step further with its 9pm watershed.

Campaigners, such as the World Cancer Research Fund (WCRF), want junk food adverts completely banned before 9pm to cut childhood obesity

Obesity is defined as an adult having a body mass index (BMI) of 30 or over.

Overweight is a less severe classification but still considered unhealthy.

A healthy person's BMI - calculated by dividing weight in kg by height in metres, and the answer by the height again - is between 18.5 and 24.9.

BMI measurements:

'Our analysis shows that introducing a 9pm watershed on unhealthy TV food advertising can make a valuable contribution to protecting the future health of all children in the UK, and help level up the health of children from less affluent backgrounds,' said study author Dr Oliver Mytton at the University of Cambridge.

Dr Mytton also stressed the importance of a junk food ad ban on other advertising mediums as well as TV.

Google has already revealed it is banning junk food adverts from being shown to children on its platforms, including YouTube.

'Children now consume media from a range of sources, and increasingly from online and on-demand services,' said Dr Mytton.

'So in order to give all children the opportunity to grow up healthy it is important to ensure that this advertising doesn't just move to the 9 to 10pm slot and to online services.'

In England, one in five children aged between four to five years and one in three children aged 10 to 11 years are overweight or obese.

Children with obesity are five times more likely to have obesity as an adult and are at increased risk of premature death and developing a range of diseases, cardiovascular disease, diabetes and some cancers.

In July, Boris Johnson's government revealed it is putting an end to junk food adverts on TV and online before the 9pm watershed in a bid to shield youngsters from obesity.

The government also launched a consultation over a total ban on junk food advertising online.

The Conservative government had announced plans to halve childhood obesity by 2030, detailed in its 'plan for action' document, back in 2018.

A Cancer Research UK survey in 2018 of almost 2,500 children found those who used the internet or watched commercial television for more than half an hour a day were more likely to ask for, buy or eat junk food.

Experts found youngsters who watched more than three hours of commercial TV a day ate an average of ten extra snack items, such as crisps, biscuits or fizzy drinks, a week compared with those who watched very little TV.

However, when they watched TV without adverts, there was no link between screen time and the likelihood of eating more junk food.

Each additional hour children spent watching commercial TV was linked to more than a 20 per cent increased chance of children craving for food they'd seen advertised or buying the food they'd seen advertised.

The children who watched more than three hours of commercial TV a day were 59 per cent more likely to be overweight or obese than children who watched half an hour a day or less.

Researchers found the primary school-age children surveyed spent an average of 16 hours a week on the internet.

Every additional hour children spent online was linked to a 19 per cent increased chance of children asking for food they'd seen advertised and a 19 per cent increased chance of buying the food they'd seen advertised.

Those who used the internet more than 3 hours a day were 79 per cent more likely to be overweight or obese than children who used the internet half an hour a day or less.

In the new study, researchers used data on children's exposure to HFSS advertising between 5:30am and 9pm, as well as previously published information on the association between exposure to HFSS advertising and children's calorie intake.

The team used data from analytics firm Nielsen on all adverts for food and drink broadcast on TV in 2015.

The dataset included details on what products and brands were advertised, the time of the advert, the channel on which the advert was shown and what programmes ran either side of the advert.

Their data also contained information on ‘child impacts’ for each advert, provided by the Broadcasters’ Audience Research Board.

The team then used computer modelling to estimate the effect of the average change in calorie consumption on the average body weight of boys and girls and their subsequent health in adult life.

The study concluded that all HFSS advertising in the UK being withdrawn during these hours would mean the 3.7 million children in the UK would see on average 1.5 fewer HFSS advertisements per day.

They would also decrease their calorie intake by an average of 9.1 calories a day.

One calorie is the amount of heat needed to cause the same increase in one kilogram of water.

'In reality some children will see a bigger effect and some a smaller or no effect –not everyone will be affected equally,' Dr Mytton told MailOnline.

This average daily decrease of 9.1 calories would reduce the number of children aged 5 to 17 with obesity by 4.6 per cent and the number of children considered overweight by 3.6 per cent.

This is equivalent to 40,000 fewer UK children with obesity and 120,000 fewer classified as overweight – 160,000 in total.

It would also result in a health-related net monetary benefit of £7.4 billion to the UK.

The team admit that they cannot accurately account for all of the factors that would affect the impact of the government's policy.

'Whilst randomised trials show that children exposed to less-healthy food advertising consume more calories, there is uncertainty about the nature of the dose-response relationship between HFSS advertising and calorie intake,' the authors say in their study, published in PLOS Medicine.

The study only considered the direct impact of HFSS advertising on children's caloric intake and did not consider the impact of HFSS advertising on changing both children's and adults' dietary preferences and habits.

Earlier this year, the World Cancer Research Fund (WCRF) slammed the UK government for delaying its decision to protect children from the effects of 'harmful' food marketing.

Ministers last year carried out a review into the effectiveness of a 9pm watershed on junk food adverts, but decided not to adopt the measure on the basis that it would be ineffective.

At the time WCRF said the government was failing children's 'basic human rights' by ignoring the evidence.

It claimed 49 per cent of the food adverts between 6pm and 9pm in May 2018 were directly advertising high fat, salt and sugar foods.

Children carrying extra weight are more likely to develop type 2 diabetes, heart disease, cancer or have a stroke in adulthood.

On the other hand, bans on HFSS ads before the watershed might make food producers struggle during an already uncertain financial period, industry figures have said.

Tim Rycroft, chief operating officer of the Food and Drink Federation, called the government's decision in July a 'slap in the face'.

'The government is about to deliver a slap in the face to the food industry which has worked so heroically over the last four months to keep the nation fed at some considerable risk to itself,' he told BBC Radio 4's Today programme at the time.

Obesity is defined as an adult having a BMI of 30 or over.

A healthy person's BMI - calculated by dividing weight in kg by height in metres, and the answer by the height again - is between 18.5 and 24.9.

Among children, obesity is defined as being in the 95th percentile.

Percentiles compare youngsters to others their same age.

For example, if a three-month-old is in the 40th percentile for weight, that means that 40 per cent of three-month-olds weigh the same or less than that baby.

Around 58 per cent of women and 68 per cent of men in the UK are overweight or obese.

The condition costs the NHS around £6.1billion, out of its approximate £124.7 billion budget, every year.

This is due to obesity increasing a person's risk of a number of life-threatening conditions.

Such conditions include type 2 diabetes, which can cause kidney disease, blindness and even limb amputations.

Research suggests that at least one in six hospital beds in the UK are taken up by a diabetes patient.

Obesity also raises the risk of heart disease, which kills 315,000 people every year in the UK - making it the number one cause of death.

Carrying dangerous amounts of weight has also been linked to 12 different cancers.

This includes breast, which affects one in eight women at some point in their lives.

Among children, research suggests that 70 per cent of obese youngsters have high blood pressure or raised cholesterol, which puts them at risk of heart disease.

Obese children are also significantly more likely to become obese adults.

And if children are overweight, their obesity in adulthood is often more severe.

As many as one in five children start school in the UK being overweight or obese, which rises to one in three by the time they turn 10.

This article is republished from Daily Mail Online. Read the original article.