They found that people on diets typically lose five to 10 per cent of their starting weight in the first six months. But up to two-thirds regain more weight than they lost within four or five years, and the true number was likely to be significantly higher.
The sad thing is this is just a systematic review of studies that have been in the literature for decades. The fact that this is news to anyone is just testimony to the power of the weight loss industry, which has been able to confuse the public about dieting and weight loss despite oceans of data (and the experience of millions of people).
The full text of the study can be found here.