“Thin equals healthy” is one of the most stubborn stories in modern medicine and culture—and it’s costing people care, dignity, and health. In part three of our myth-busting series, Michelle traces how BMI became medical shorthand, why correlation isn’t causation, and how well-designed studies (and a mountain of confounders like fitness, nutrition, access to care, stigma, and weight cycling) upend the simple “smaller is better” narrative. You’ll hear how weight stigma harms outcomes for people in all body sizes, why intentional weight loss doesn’t translate to long-term health, and what a weight-inclusive approach looks like in real life—behaviour-first, shame-free, and actually sustainable.