27-05-2025
Obese people can pass down deadly health risk to their children, study finds
Boys who pile on the pounds in their early teens could put their future children at higher risk of developing obesity and asthma, according to a new study.
While it's normal for teenagers to put on weight as they grow, some children gain too much thanks to a lack of exercise and reliance on sugary, salty snacks.
Now, experts have discovered that overweight teenage boys risk damaging the genes of their future children.
And it shows this time of life – when sperm is developing - is a 'key window of vulnerability' for DNA.
The team, from the University of Southampton and the University of Bergen in Norway, analysed the DNA of 339 pairs of fathers and their offspring.
As part of their long-term study, they also collected data on fathers' body silhouettes during adolescence.
Analysis revealed DNA changes in 1,962 genes linked to the formation of fat cells and fat metabolism in the children of fathers who gained too much weight as teenagers.
These changes were associated with an increased risk of obesity, as well as asthma and poorer lung function.
In bad news for daughters, the effect was more pronounced in female children than male children.
'The overweight status of future fathers during puberty was associated with a strong signal in their children's DNA which were also related to the likelihood of their children being overweight themselves,' Dr Negusse Tadesse Kitaba, one of the study's authors, said.
'Early puberty, when boys start their developing sperm, seems to be a key window of vulnerability for lifestyle influences to drive epigenetic changes in future offspring.'
Male puberty typically begins between the ages of 9 and 14, with an average start around the age of 12.
Professor Cecilie Svanes from the University of Bergen said: 'The new findings have significant implications for public health and may be a game-changer in public health intervention strategies.
'They suggest that a failure to address obesity in young teenagers today could damage the health of future generations, further entrenching health inequalities for decades to come.'
In children and teens, BMI is used to find out if they are underweight, a healthy weight, overweight or obese.
The latest NHS figures show that 32 per cent – nearly a third – of children aged 11-12 in England are overweight or obese.
This dips slightly to 25 per cent in children aged 13-15.
Experts recently warned that adolescent health is at a 'tipping point', and that some of the main drivers of ill-health among teenagers have switched from cigarettes and alcohol to weight gain and mental health problems.
Commenting on the recent findings Professor John Holloway, who was also involved in the study, said: 'Childhood obesity is increasing globally. The results of this study demonstrate that this is a concern not only for the health of the population now but also for generations to come.'
To help a teenager lose weight, the NHS suggests a combination of healthy eating and regular physical activity.
Gradual changes – such as introducing better portion control and finding fun activities to do – is encouraged in the place of fad diets or skipping meals.
The findings were published in the Nature journal Communications Biology.
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.
