The pursuit of a leaner, more muscular physique has physiological limits for women, according to a fitness article in Der Spiegel. It examines when fat loss can hinder muscle growth and why eating protein alone may not be enough to support both goals.
The article also points to changes in the menstrual cycle as a possible warning sign. The available text does not provide further details about the research or the guidance offered by the scientist interviewed.
Sources: Der Spiegel.