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Energy Availability Restriction

Meaning

Energy Availability Restriction is a state where the dietary energy intake remaining after accounting for the energy expended through exercise is insufficient to support the body’s essential physiological functions, including cellular repair and hormonal production. This restriction is a clinical metric, not merely a caloric deficit, and is expressed as energy remaining per kilogram of fat-free mass. Prolonged restriction triggers a cascade of adaptive, survival-oriented endocrine changes, most notably the suppression of the reproductive, thyroid, and growth hormone axes, as the body attempts to conserve resources. This is a critical factor in understanding hypothalamic amenorrhea and other forms of functional endocrine disruption.