Should think that "Only fit able-bodied should apply" is simply illegal in many jurisdictions. Would medically-overweight wheelchair-bound black gays be rejected and on which grounds? At least one or two might prevent them entering the "wall sit time" competition... None should be relevant factors for hiring.
It's one thing to restrict sugar at the office, it's another if they actual hire for office jobs based on age, disability, or genetic testing.
Obesity, FYI, has not been classified as a disability. http://time.com/4883176/weight-discrimination-workplace-laws... https://www.lexology.com/library/detail.aspx?g=a2bcd2c9-9e60... In most of the US, "Must have BMI 18-24" is a legally permissable (albeit unwise) employment retirement.
Also "employer" in this context requires 15+ employees.