Keto And Periods: What's The Connection?

The keto diet is a popular, high-fat, low-carb approach to weight loss that has been linked to a host of health benefits. However, it may also affect your menstrual cycle. Some women who follow the keto diet report irregular periods, while others say their monthly cycle stopped altogether – a phenomenon called amenorrhea. In fact, weight loss and amenorrhea are the two main side effects of the diet. So, does starting keto trigger a period? The answer is: it depends.

Keto can cause rapid weight loss, which can lead to irregular periods

The keto diet is a low-carb, high-fat diet that can often lead to rapid weight loss. This rapid weight loss can cause hormonal changes that may influence the menstrual cycle.

When a person loses weight, their estrogen levels drop. Estrogen is one of the main hormones that regulate the menstrual cycle. As weight drops, so do estrogen levels, which can lead to irregular periods or amenorrhea (the absence of a menstrual cycle for three months or more).

Angela Chaudhari, a gynecologist at Northwestern Memorial Hospital, explains that "rapid weight loss can alter your estrogen-progesterone balance and impact ovulation, therefore causing your periods to become more irregular."

Additionally, when a person restricts their calorie intake too much, it can trigger a stress response in the body. This stress can also affect the menstrual cycle.

While keto can cause irregular periods due to rapid weight loss, it's important to note that this is not exclusive to the keto diet. Any diet that results in rapid weight loss can have similar effects on the menstrual cycle.

Furthermore, the keto diet may also improve reproductive health in women with polycystic ovarian syndrome (PCOS). By reducing inflammation and insulin resistance, keto can help regulate estrogen production and improve ovulation.

If you're experiencing irregular periods while on the keto diet, it's recommended to ensure you're consuming enough calories and nutrients. Consider scaling back on fasting and incorporating more nutrient-dense whole foods into your diet. If issues persist, consult a doctor or healthcare professional.

Extreme carbohydrate restriction may cause amenorrhea or hypomenorrhea

Chaudhari also notes that rapid weight loss, which can occur on the keto diet, can alter the estrogen-progesterone balance and impact ovulation, leading to irregular periods. This can further cause anovulation, or a lack of ovulation, resulting in amenorrhea. While these changes in the menstrual cycle are likely due to rapid weight loss, they are not exclusive to the keto diet and can also occur due to a very low-calorie diet, excessive exercise, or a very low BMI.

Additionally, a drop in carbohydrates has the potential to affect thyroid hormone production, which can also influence the menstrual cycle, especially in individuals with thyroid-related diseases. Overall, while the keto diet may offer weight loss and health benefits, it is important to be aware of its potential impact on the menstrual cycle and seek medical advice if irregularities occur.

Calorie restriction can interfere with the female reproductive cycle

Calorie restriction can also impact the function of the ovaries, including folliculogenesis, ovulation, and steroidogenesis. It can delay the onset of puberty and affect the quality of eggs, potentially leading to infertility or irregular menstrual cycles. The severity of these effects may depend on the degree of calorie restriction, with more profound restrictions having more significant impacts.

Furthermore, calorie restriction has been linked to conditions such as hypothalamic amenorrhea, which is characterized by impaired HPG axis function and anovulation. It is also worth noting that the impact of calorie restriction on the female reproductive cycle may be influenced by other factors, such as age, physical activity levels, and overall health status.

Overall, while calorie restriction can interfere with the female reproductive cycle, the specific effects may vary depending on the individual and the extent of the calorie restriction.

Keto can be stressful, which can disrupt the menstrual cycle

Starting a keto diet can be stressful, and stress is a well-documented disrupter of the menstrual cycle. The stress hormone cortisol can bind to most cells in the human body, including cells that influence reproductive health.

Dietary changes can be difficult, and giving up carbs can be uniquely stressful. If you are also experiencing keto flu symptoms from carb withdrawal, that's stressful too, even if you know the symptoms are temporary.

Calorie restriction is another way that keto may disrupt the menstrual cycle. Because keto reduces hunger hormones, many people end up eating fewer calories overall. Unfortunately, significant calorie restriction can interfere with the female reproductive cycle. Too much calorie-cutting on keto can also interfere with thyroid function, and disruptions in thyroid hormones are linked to disruptions in menstruation.

If you decide to experiment with keto during your reproductive years, it's important to ensure you are consuming enough calories. It's easy to undereat on keto, so track your food intake with an app and supplement with keto-friendly snacks as needed.

Thyroid function may be impacted by keto, leading to menstrual irregularities

Starting a keto diet can trigger menstrual irregularities. While the keto diet is often associated with weight loss and other health benefits, it can also affect a woman's menstrual cycle. This is mainly due to the rapid weight loss that can occur on a keto diet, which can alter the estrogen-progesterone balance and impact ovulation, leading to irregular periods or amenorrhea (the absence of periods).

The keto diet's reduction in carbohydrates can put the body into a state of ketosis, which is characterised by elevated levels of ketones. While in ketosis, the body may struggle to convert the inactive thyroid hormone thyroxine (T4) into the active form triiodothyronine (T3). This is because thyroid hormones play a significant role in glucose metabolism, and too little insulin can impair the liver's ability to convert T4 to T3. Additionally, when the body remains in ketosis for extended periods, accumulated acidity can lead to inflammation, which may further interfere with thyroid function, especially in individuals with hypothyroidism who already deal with chronic inflammation.

Furthermore, calorie restriction, which often occurs on a keto diet due to reduced hunger hormones, can also interfere with thyroid function. Disruptions in thyroid hormones, such as T3 and T4, are linked to disruptions in menstruation. However, it is important to note that while thyroid hormones may decline on low-carb diets, there is some evidence that these diets may be therapeutic for certain thyroid disorders.

To summarise, the keto diet's impact on thyroid function, particularly through carbohydrate and calorie restriction, can lead to menstrual irregularities. However, the relationship between diet, thyroid function, and menstruation is complex and varies from person to person. It is always advisable to consult with a healthcare professional before making significant dietary changes, especially if you have an existing thyroid or reproductive health condition.

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