French actress Catherine Deneuve’s famous declaration that, after age 30, a woman has to choose between her face and her ass now has scientific backup. A major new study into the causes of ageing, from Case Western Reserve University in Cleveland, Ohio, confirms that being thin is what ages us most. The conclusion was drawn after the team studied nearly 200 pairs of identical twins over two years. “A BMI higher by four points was found to result in a younger appearance of between two to four years in women over 40 years old,” said Bahaman Guyuron, the plastic surgeon who led the study. Rajiv Grover, secretary of the British Association of Aesthetic Plastic Surgery, welcomed the findings. “It gives scientific credence to what we always thought but couldn’t prove, which is that it is not what your mother looks like, but volume-loss that makes you look older,” he says. “Excessive dieting will give a woman a gaunt appearance by leading to volume loss in the midface [cheeks],” adding volume loss can be compounded by yo-yo dieting.’ Other factors found to contribute to ageing include sun damage, smoking, drinking, failure to cope with stress and long-term anti-depressant use.