Correction: Call for an urgent rethink of the 'health at every size’ concept

The argument for an urgent rethink When I (AS) was a child, my grandmother used to say “Don’t pull an ugly face, because if the wind changes, your face will become stuck like that”. I don’t know what evidence my grandmother had for this advice, but as a neuroscientist who studies the effects of diet on the hypothalamic control of appetite and body weight, I say “Don’t eat an ugly diet or let yourself stay fat, because if the wind changes you may become stuck with permanent obesity.” The long-term effects of excess calories and adiposity on body weight regulation appear to have been overlooked in the fat acceptance movement that has emerged in parallel with the obesity epidemic. In this commentary I outline the possibility that excess body fat and its underlying contributors lead to permanent changes in the brain pathways that control body weight, and call for urgent reconsideration of the ‘health at every size’ concept. While I certainly agree that it is possible to have healthy behaviours that provide health benefits at a wide variety of body sizes, I disagree that it is possible to be – or to stay – truly healthy at every size. The World Health Organisation decrees that a body mass index (BMI) of 18.5 to 24.9 kg/m is generally optimum for health, at least for Caucasians between the ages of 18 and 65 [1]. However, there are many people who are healthy who have a BMI outside this range. For instance, some people self-impose long-term calorie restriction and generally have a low BMI and exhibit metabolic benefits, in keeping with animal studies which show that long-term calorie restriction prolongs life [2]. There are also people with a BMI in the overweight (≥ 25 kg/m) or obese (≥ 30 kg/m) range that exhibit no signs of eminent metabolic disease whatsoever, and these are not limited to people who are body builders or elite athletes [3]. Moreover, overweight or obese