Did you know that your nutritional needs change throughout your menstrual cycle? Female hormone levels vary throughout the menstrual cycle and can impact everything from exercise performance, substrate utilization, metabolic demand, and nutrient needs. And while you cannot always plan when you have an important competition or game, you can tailor your nutritional strategies to optimize performance based on hormonal fluctuations.
In this article, we discuss hormone fluctuations throughout a typical cycle, how these fluctuations can impact a female athlete’s needs, and some tips on how to adjust for different phases of your cycle.
How do your hormones change throughout your cycle?
Hormones fluctuate throughout the month depending on the phase of the menstrual cycle. A typical cycle lasts on average 28 days but can range from 21 to 45 days. Cycles have two distinct phases, the follicular phase (day 1-14) and the luteal phase (day 15-28).
The follicular phase is when menstruation occurs. Hormone levels (estrogen, luteinizing hormone(LH), progesterone, follicle-stimulating hormone(FSH)) are at their lowest during the beginning of the follicular stage. Estrogen and FSH start to rise around day 4 or 5 of this phase to prepare the body for ovulation. At the end of the follicular phase, LH spikes due to the increase in estrogen, and ovulation occurs. The luteal phase then begins, and these hormones start to decline.
Do calorie and macronutrient needs change during your cycle?
Consuming adequate calories and macronutrients is necessary for athletes to have the energy necessary to perform, but also to support proper hormone function. Resting energy expenditure increases anywhere from 2-11.5% during the luteal phase (second half of your cycle). This could explain why an athlete may feel hungrier towards the end of their cycle. We always recommend athletes listen to their body, and this could be a good opportunity to add in a well-balanced snack throughout the day.
Macronutrients
Carbohydrates throughout your menstrual cycle
Depending on the phase of your cycle, substrate utilization (i.e. what macronutrient your body is utilizing most as fuel) and nutrient needs can change. Carbohydrate oxidation (using carbohydrates for energy) increases during the follicular phase, while glycogen storage is decreased. Because of this, the follicular phase may better support intense exercise, but female athletes should prioritize consuming carbohydrates before exercise to ensure they have adequate energy to perform.
Importance of Adequate Fat for menstrual function
Consuming enough dietary fat is essential for supporting hormone production. Fat also acts as an energy source for low-intensity exercise. Due to the decrease in estrogen during the luteal phase, carbohydrate oxidation decreases and the body relies more on fat oxidation, which may better support low-intensity exercise. Athletes should aim to consume at least 20% of their total daily calories from fats, and prioritize sources like avocados, nuts, seeds, olives, oils like avocado and olive oil, and fatty fish. Consuming less than this amount could lead to deficiencies in essential fatty acids and fat-soluble vitamins such as vitamin A, D, E, and K, and increase the risk of low energy availability and menstrual dysfunction.
Protein throughout your cycle
Protein has many important roles in the body including building and repairing lean muscle mass, supporting bone health, and making up hormones, enzymes, and antibodies. Progesterone and estrogen levels peak during the mid-luteal phase (days 20-24). During this time, protein oxidation is increased and plasma amino acid concentration decreases, so increased protein intake during this time can be beneficial. Female athletes should aim for 1.6 g/kg (.73 g/lb.) of protein a day. For a 170 lb. female athlete, this would be 124 grams of protein per day. We recommend athletes consume protein consistently throughout the day, including a protein source at every meal and snack.
Do you need to supplement during your cycle?
Certain nutrient needs increase during menstruation and micronutrient (vitamin and mineral) deficiencies can negatively impact overall health, athletic performance, and increase the risk of injury for athletes. Female athletes are often lacking in folate, riboflavin, vitamin B12, vitamin D, and iron.
Creatine, omega-3 fatty acids, protein, and caffeine are all supplements that have been shown to be safe and effective in female athletes. We always recommend focusing on consuming these nutrients from food first as much as possible, and then supplementing as needed.
Specific needs for calories, macronutrients, and supplements should still be individualized to the athlete, but the recommendations outlined in this article are likely a universal starting point. If you are interested in an individualized nutrition plan to meet your needs and goals, head to our contact page to apply for nutrition coaching.
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