It can not be argued that a ballerina's body is normal for the vast majority of the population. Plenty of talented ballet dancers will not 'make it' simply because their bodies don't or can't conform to what a ballet dancer's body should look like. So professional ballet dancers are a group already set apart by their body shape and type even before training regimes and diets are taken into account.
The bodies of professional dancers, cyclists, athletes are difficult to emulate on a hobby basis. How can an average person, working a forty hour week and training on top possibly hope to match the physicality of a sports person whose full time job is training and competing? When again those professionals are already where they are because their bodies are exceptional, not normal.
I know a former professional cyclist who was stick thin despite eating around 10,000 calories a day because the level of training he undertook was astonishing. He looks more 'normal' now he is living like the rest of us.
I also know someone who ran in the London Marathon this year. They had followed a proper training schedule over a period of many months and were rewarded with a good time in the race. In comparison to Cheryl (if she is being used as the yard stick for how we should look) they remained very overweight, before during and after.
Elite athletes are not normal, they don't have bodies like the rest of us, we don't have bodies like them.
Arguing that Cheryl's current figure is normal is bonkers as is justifying the argument by comparing her to elite athletes.
Jo Brand doesn't have a normal figure either.