A person's risk of needing obesity treatment is largely determined by their genes, a new study has found.
Researchers at Tel Aviv University carried out a study involving 3,000 middle-aged women in the UK, all of whom were identical or fraternal twins.
They measured participants' 'total lean mass', which is a major component of body weight, and compared this with markers in their genes.
Analysis revealed that, in more than 50 per cent of cases, the women's body sizes could be predicted by their genes.
The findings are published in the Journal of Clinical Epidemiology & Metabolism.
Professor Gregory Livshits, who carried out the research in collaboration with experts at King's College London, commented: "The bad news is that many of our physical features, including our weight, are dependent on our genes.
"The good news is that women still have an opportunity to go against their genetic constitution and do something about it."
However, the expert admitted that people with certain genes would only be able to lose weight "with much difficulty".