Whether a woman is an apple or pear shape, or if a man has a ‘beer belly’, depends on their genes, research suggests.
A study of more than 360,000 volunteers found where a person stores their fat is determined by 98 points in their DNA.
Swedish researchers found the genetic effects of where fat is stored were strongest in women – but also played a small role in men.
They hope their findings will lead to new drugs that prevent fat building up around the midriff, strongly linked to heart disease.
Whether you are an apple or pear shape depends on your genes, research suggests (stock)
‘We know that women and men tend to store fat differently,’ said lead author of the study, Dr Mathias Rask-Andersen of Uppsala University.
‘Women have the ability to more easily store fat on the hips and legs, while men tend to accumulate fat around the abdomen to a higher extent.
‘This has been attributed to the effects of sex hormones such as oestrogen. But the molecular mechanisms that control this phenomenon are fairly unknown.’
After puberty, women tend to gain weight on their hips and legs, while men are more at risk of a beer belly.
Storing fat on your front is associated with a higher risk of heart disease in both men and women due to fat then accumulating around the vital internal organs.
Body fat distribution is increasingly being used to assess obesity over BMI, due to it more accurately reflecting fat around the organs.
To test how fat distribution is affected by genes and varies between the sexes, the researchers analysed 362,499 volunteers from UK Biobank.
The volunteers gave blood samples to assess their DNA, and had their fat distribution measured via by passing an electrical current through parts of their bodies and seeing the level of resistance.
Millions of genetic mutations were assessed to determine whether they influence fat storage.
The researchers discovered 98 ‘genetic signals associated with fat distribution’, of which 29 had not previously been identified.
And 37 of these were shown to be particularly strong in women.
Men were found to carry 62.2 per cent of their fat on their front versus just 50.3 per cent in women.
While females carry 39.7 per cent of their fat in their legs compared to only 28.1 per cent in males.
Fat distribution in the arms was similar between the sexes.
The genes behind fat storage are thought to influence the make up of the extracellular matrix. This includes collagen, enzymes and proteins, which provide structural support to surrounding cells.
Group leader Åsa Johansson, a docent, said: ‘We were struck by the large number of genetic effects that were stronger, or only present, in females.
‘Upon closer examination, several of the associated genes were found to encode proteins that actively shape the extracellular matrix, which makes up the supporting structure around cells.’
The researchers hope their study will lead to the development of new interventions that reduce the risk of heart disease.
‘The biological systems we highlight in our study have the potential to be used as points-of-intervention for new drugs that are aimed at improving the distribution of body fat and thereby reducing the risk of disease,’ Dr Rask-Andersen said.
Obesity affected 26 per cent of adults in the UK in 2016 – up from 15 per cent in 1993, NHS Digital statistics reveal.
And around 39.8 per cent of people in the US were carrying dangerous amounts of weight between 2015 and 2016, according to the Centers for Disease Control and Prevention.
‘Obesity is set to become the world’s leading preventable risk factor for disease and early death due to the increased risks of developing type 2 diabetes, cardiovascular disease, and cancer,’ the researchers wrote in the journal Nature Communications.