📋 THE STUDY
🔬 WHAT THEY DID
Study design: Systematic literature review of 14 studies
Who was studied: 204 recreationally active or competitive pre-menopausal female athletes (ages 18–45) across the 14 studies
How long: The review analyzed literature from database inception up to March 2020; included studies ranged from single-session interventions to 8-week training programs.
What they measured: Daily protein requirements (Estimated Average Requirement), acute protein needs (pre-, during, or post-exercise), and physiological responses such as nitrogen balance, muscle protein synthesis, and performance.
Funding: No external funding reported.
📊 WHAT THEY FOUND
The study confirms that daily protein needs for female athletes across all sport types fall within the standard recommended range of 1.2–2.0 g/kg, regardless of the specific exercise modality.
Main finding 1: The estimated daily protein requirement for female athletes falls between 1.28 and 1.63 g/kg/day, which is consistent across aerobic endurance, resistance, and intermittent exercise types.
Main finding 2: While an "optimal" acute dose was not determined, consuming 0.32–0.38 g/kg of protein pre- or post-exercise is associated with beneficial responses, such as improved recovery and increased strength, particularly for resistance and intermittent exercise.
Main finding 3: The researchers were unable to determine if the menstrual cycle phase or the use of hormonal contraceptives changes protein requirements due to a lack of sufficient data in the available studies.
⚠️ LIMITATIONS
The conclusions are limited by a scarcity of data, particularly regarding how the menstrual cycle and hormonal contraceptives might alter protein metabolism.
Small number of studies. Only 14 studies met the inclusion criteria, meaning the findings are based on a relatively small total population (204 participants) and may not fully reflect the training schedules and energy balance of elite athletes.
The "hormone gap" remains. The study could not draw conclusions regarding the influence of the menstrual cycle or contraceptives. This means we still do not know if female athletes need to adjust their protein intake during specific hormonal phases (e.g., the luteal phase).
Methodological variance. Some data relies on the "nitrogen balance" method, which has limitations and may overestimate protein requirements compared to other methods. Differences in protein quality (animal vs. plant) were not fully explored, as most studies used high-quality whey or egg protein.
💡 BOTTOM LINE
Current general sports nutrition guidelines (1.2–2.0 g/kg/day) appear adequate for pre-menopausal female athletes, but there is not yet enough evidence to create specific recommendations tailored to menstrual phases or hormonal contraceptive use.
🔗 MORE TO EXPLORE
