Pro tip: If you suddenly feel the urge to make an unsolicited comment on someone's weight, don't.

All too often, fat people are victims of body-shaming disguised as "concern." It's impossible to determine a person's health by their physical presentation, but that doesn't stop people from giving their unprofessional diagnoses in public and online.

Though being underweight causes more health problems than being overweight, let's be real: anyone who feels compelled to comment on a stranger's body doesn't care about that. They're just afraid of fatness.