The Short Version
While fasting does acutely raise cortisol and women show sex-specific changes in cortisol rhythm, the peer-reviewed evidence does not establish that fasting is clinically harmful for women with pre-existing high cortisol levels. The claim conflates a measurable hormonal response with demonstrated health harm—a logical leap unsupported by the highest-quality studies available. Sources making the stronger causal claim are predominantly wellness blogs and commercial health platforms, not clinical research on this specific population.