Chemical in food wrappers ‘makes women gain weight’

CHEMICALS used in nonstick pans, food wrappers and waterproof coats may be contributing to obesity, scientists warned last night. The compounds, known as perfluoroalkyl substances or PFASs, are believed to reduce human metabolism.

It is thought that this is because they disrupt hormones – particularly the female sex hormone oestrogen, which controls body weight. They may thus be a factor in yo-yo dieting, where women tend to pile on the pounds again after slimming.

PFASs have been used for more than 60 years but have been linked with cancer as well as raised cholesterol levels.

Their widespread use means traces have been found in human breast milk as well as blood, while British studies have detected the chemicals in our drinking water and the fish we eat. A US-led study of more than 600 people found those with high levels of PFASs in their blood are more likely to regain weight after dieting.

For women, this could mean a difference of almost 5lb in the weight they put back on.

Researchers found the chemicals are linked to lower metabolism, so people burn fewer calories making it harder to prevent weight gain as they need less food. The study’s lead author, Dr Qi Sun from Harvard T H Chan School of Public Health, said: ‘Our findings have revealed a novel pathway through which PFASs might interfere with human body weight regulation and thus contribute to the obesity epidemic.’

PFASs were devised principally to create non- stick coatings for pans and water-repellent and stain-resistant coatings for fabrics and furnishings. They are also found in ski waxes, leather goods, fire-fighting foams and paints, and are valued for their chemical stability – it takes a long time for them to break down.

But concerns are growing about the risk of being exposed to them through household items.

The study, published in the journal PLOS Medicine, analysed data from 621 overweight and obese people in a clinical weight-loss trial from the mid-2000s.

They compared the amount of PFASs in the subjects’ blood as they entered the study and their weight measurements during and after dieting.

During the first six months of the trial, participants lost an average of just over a stone in weight ( 6.4kg), but regained almost 6lb (2.7kg) during the following 18 months.

Those who put the most weight back on also had the highest blood concentrations of PFASs, and the link was strongest among women. On average, women in the top third for blood levels of PFASs regained 3.7lb to 4.9lb (1.7kg to 2.2kg) more weight than women in the lowest third.

In addition, those with higher concentrations of PFASs in the blood appeared to have lower resting metabolic rates.

This means their body burns fewer calories from their food, so they would struggle to maintain a lower weight and could fall victim to yo-yo dieting.

Study co- author Professor Philippe Grandjean said: ‘We typically think about PFASs in terms of rare health problems like cancer, but it appears they are also playing a role in obesity, a major health problem facing millions around the globe.

‘The findings suggest that avoiding or reducing PFAS exposure may help people maintain a stable body weight after they successfully lose some weight, especially for women.’

‘Contributing to obesity’