“Slim doesn’t always mean healthy” and such claptrap is functionally equivalent to a lie, though it’s semi-true just often enough that it’s not quite a complete fabrication.

The truth of course is that being slim means someone is far more likely to be healthy and stay that way. Where the Fat Acceptance and related self-harm movements allow their nonsense to slide in is that some (a few) slim people are in fact unhealthy. Those such as anorexics, cancer patients and people with genetic defects can be svelte but on the edge of death.

This allows in the faulty logic that slim == bad. Which of course is heavily promoted by the obesity-benefting food industry in the US.

Fat Acceptance really did a number on us (with food industry financial and propaganda assistance).