Everyone knows someone who seems to be able to eat what they want, when they want and never put on weight.
Case in point Ria Carroll from Essex, who was filmed for Channel 4Ã¢â‚¬â„¢s Ã¢â‚¬ËœThe Secret Lives of Slim PeopleÃ¢â‚¬â„¢ in a bid to find out how she maintains her slim 9st 4lb figure, despite doing no exercise and existing on a diet of takeaways, biscuits and junk food.
While many of us wonder what the secret might be for people who stay so slim without exercising and eating healthily, experts believe the rumours are true and it really might be down to genes.
Despite RiaÃ¢â‚¬â„¢s bad food habits and lack of exercise, experts credited her parentsÃ¢â‚¬â„¢ and grandparentsÃ¢â‚¬â„¢ slim size, claiming she maintains her figure because sheÃ¢â‚¬â„¢s genetically predisposed to staying thin.
Camera footage of RiaÃ¢â‚¬â„¢s daily life, which included snacking on biscuits in bed and eating more than 2,800 calories a day, well over the recommended 2,000.
Professor Sadaf Farooqi, from the Wellcome Trust Ã¢â‚¬â€œ MRc Institute of Metabolic Science Addenbrookes Hospital, in Cambridge, explained that a recent study revealed that some people are biologically predisposed to being slim.
The investigation looked at 1,600 healthy, very slim people with a body mass index of less than 18 Ã¢â‚¬â€œ which is generally considered underweight by the NHS, who deem 18.5 to 24.9 as the Ã¢â‚¬Å“healthyÃ¢â‚¬Â range.
Lifestyle questionnaires ruled out the possibility of eating disorders in these individuals.
These individuals were compared to 2,000 severely obese people and 10,400 people of a normal weight.
The Ã¢â‚¬Å“skinnyÃ¢â‚¬Â subjects were found to have fewer genes linked to obesity, as well as certain genes associated with thinness.
Meanwhile, on average the severely obese individuals were more likely to possess a gene set linked to obesity.
Ã¢â‚¬Å“Thinness is highly heritable, which means it runs in families,Ã¢â‚¬Â Professor Farooqi explained to the presenter.
Ã¢â‚¬Å“There are some genes that predispose people to gaining weight and some people who struggle with their weight have more of those genes.Ã¢â‚¬Â
She went on to say that this does seem like something people have long suspected but this is the first time they have scientific evidence to back it up.
Ã¢â‚¬Å“This research shows for the first time that healthy thin people are generally thin because they have a lower burden of genes that increase a personÃ¢â‚¬â„¢s chances of being overweight and not because they are morally superior, as some people like to suggest,Ã¢â‚¬Â Professor Sadaaf Farooqi previously said of the study.
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FarooqiÃ¢â‚¬â„¢s words call out the practice ofÃ‚Â body shaming, where people are stigmatised for their body shape or size.
Ã¢â‚¬Å“ItÃ¢â‚¬â„¢s easy to rush to judgement and criticise people for their weight but science shows that things are far more complex.
She added: Ã¢â‚¬Å“We have far less control over our weight than we might wish to think.Ã¢â‚¬Â
Following the revelation Ria revealed that her parents have always been slim, as were her grandparents, meaning it is possible her slim figure could be attributed to her genetic disposition.
And people on Twitter were pretty interested in the new reasoning for some people staying slim.