Traditionally, women and men have followed the same nutritional and training guidance. However, Dr Stacy Sims, an exercise physiologist and nutrition scientist who specialises in women, emphasises that they have unique nutritional and training needs due to their physiology and hormonal cycles.
Thus, the expert notes that, unlike men, women have more oxidative muscle fibres, which naturally make them more metabolically flexible. This fact is central to Sims’s approach, as it discourages practices that are typically promoted universally, as they are considered inappropriate or ineffective for women.
The danger of fasting
The expert explains in an interview on the podcast hosted by neuroscientist Dr David Huberman that fasting or fasted training is detrimental for women. She states that these practices increase cortisol levels and bodily stress, potentially disrupting the function of neurons that regulate appetite, oestrogen, luteinising hormone and thyroid function. In fact, thyroid dysfunction and changes in hormonal pulses have been observed after as little as four days of fasting in women.
Rather than fasting, Sims advocates circadian nutrition: breakfast within 30 to 60 minutes of waking to regulate cortisol and signal the hypothalamus about the availability of nutrients.
Regarding pre‑training nutrition, the doctor offers clear and specific guidelines:
- Before strength training she suggests consuming around 15 grams of protein.
- Before cardio workouts, she recommends 15 grams of protein plus 30 grams of carbohydrates.
Additionally, the expert stresses the importance of a high overall protein intake, proposing to reach 1 to 1.2 grams of protein per pound of body weight—about 450 g daily—to maintain muscle mass, a need that becomes even more crucial as women age.
Training: intensity, endurance and cycles
Dr Sims is an advocate of a polarised training approach for women, prioritising high‑intensity work and recovery, while minimising excessive moderate‑intensity exercise. This includes 3–4 resistance training sessions per week and 1–2 sessions of high‑intensity interval training or sprint interval training.
A lo largo de la vida de la mujer, el entrenamiento debe ajustarse de esta manera, según la experta:
- Años reproductivos: el ciclo menstrual impacta la capacidad de entrenamiento. Desde el inicio de la menstruación hasta la ovulación, las mujeres gestionan mejor el estrés y el trabajo de alta intensidad, siendo este un buen momento para entrenar hasta el fallo para la fuerza. En la fase lútea, la experta recomienda seguir patrones individuales y aumentar la ingesta de carbohidratos y proteínas en la semana previa al periodo para mantener el rendimiento.
- Durante el embarazo: el objetivo es mantener la condición física, no ganar. El cuerpo reduce naturalmente la capacidad anaeróbica.
- Perimenopausia y menopausia: el énfasis cambia al mantenimiento de la densidad ósea y muscular. Es vital realizar entrenamiento de resistencia con peso pesado, manteniendo dos a tres repeticiones en reserva, evitando el fallo, sumado a entrenamiento de intervalos de sprint. Se recomienda incorporar 10 minutos de entrenamiento de salto tres veces a la semana para mejorar significativamente la densidad ósea.
Recovery with sauna
For recovery in all cases, the expert recommends prioritising heat exposure, such as a Finnish sauna at 60–80 °C for 30 minutes after resistance training.
Finally, Stacy Sims emphasises that women should understand their physiology and listen to their bodies to incorporate exercise and nutrition strategies that are truly beneficial for their health and individual goals.
