The ketogenic diet has been gaining popularity in mainstream media. Everywhere you look, there seems to be yet another article or video touting the purported benefits of eating keto; bloggers refer to it as a fat loss miracle, influencers describe it as a way to supercharge your cognitive function.
With so much recent buzz about the keto diet, you may be wondering if it’s a good fit for you. If you’re a woman, the answer may be more nuanced than you expect. Let’s start by separating fact from fiction.
What is The Keto Diet?
The human body is an incredibly adaptive system. From an evolutionary standpoint, this has allowed us to thrive in changing seasons, and to be one of the few mammals to populate a wide range of geographic zones, with varying food sources and temperatures.
Under normal circumstances, the primary source of energy for the body - especially the brain - is glucose. We typically get glucose from carbohydrates such as rice, bread, fruit, grains, and starchy vegetables.
We haven’t always had the luxury of regular access to carbs. Thus, the body has evolved to make do with what’s available - this is where the state of ketosis comes in. During times of food shortage and an absence of carbohydrates, the liver begins to break down fats and proteins into glucose through a process called gluconeogenesis. A by-product of this process also forms - ketones (hence the ‘keto’ diet).
Is the Keto Diet Stressful to the Body?
In other words, the ketogenic diet mimics starvation - a very stressful state for the body, which is incompatible with reproduction and fertility. If your body thinks you’re starving, it’s going to shut off the energy-expensive process of reproducing. One could think of it like frostbite – if you’re at risk of freezing, your body will restric blood flow to your core to protect vital organs, potentially sacrificing non-essential fingers and toes.
During periods of high stress - such as while following a diet that mimics starvation - our adrenal glands produce more cortisol. Additionally, the process of gluconeogenisis – in which the liver breaks down fat and protein when carbohydrates are not available – requires our bodies to produce and use even more cortisol.
In order to manufacture cortisol, the glands steal raw materials that would otherwise be used to make sex hormones. Furthermore, elevated cortisol disrupts glands and functions at all levels of the sex hormone cascade. (Have you ever seen your period delayed after a stressful event? This was cortisol at work.)
Does the Keto Diet Cause Hormonal Disruptions?
The keto diet has primarily been prescribed to patients who have drug-resistant epilepsy and seizure episodes. In a number of studies, very low carb intakes have been shown to result in fewer seizures for the subjects. A ketogenic approach has also shown to have anti-tumor effects in certain cancers.
But let’s also take a look at how the diet could impact a person’s hormones.
Two of the hormones most critical to metabolism are leptin and insulin. Insulin rises in response to carbohydrate intake. The incredibly low carbohydrate intake that is necessary to trigger ketosis results in very low levels of insulin, and consequently, leptin. Leptin, triggered by a rise in insulin to register that a meal has filled you up, also signals to a woman’s ovaries that she is nourished enough to reproduce.
In one study of the keto diet on patients between the ages of 12 and 19, 45% of all girls reported menstrual problems (1). Three of the girls reported delayed puberty, and two young women were treated with hormonal contraceptives to artificially regulate their cycles. In a second study on the ketogenic diet, 100% of the female subjects reported menstrual irregularities (2).
In both of these studies, researchers described the disruption or absence of menstrual cycles as merely “side effects,” and concluded that the ketogenic diet is safe.
Even if you’re not planning to have children soon (or ever!), a regular menstrual cycle is a critical marker of good health, often referred to as the fifth vital sign. These disruptions in sex hormones can have adverse long-term effects in women: when ovulation stalls, estrogen falls, thereby hindering a woman’s ability to build and maintain proper bone density (3).
Furthermore, if a woman takes hormonal birth control - the contraceptive of choice for 46% of women - any hormonal imbalances will be masked by the artificial cycle created by her birth control (4). In plain english: a keto diet could throw a woman’s hormone’s totally out of whack, putting her at risk for osteoporosis, and thanks to her pill, she might not have any idea of what’s happening to her body.
Women are also more susceptible to developing hypothyroidism, and the science points to that risk being elevated by a ketogenic diet. A study of 120 patients concluded that the keto diet caused “thyroid malfunction and {thyroid hormone} treatment may be required. {...} Thyroid function should be monitored regularly in epileptic patients treated with {keto.}”
However as a counterpoint, it is worth noting that the ketogenic diet has been shown to have positive effects on obese patients in the areas of improved leptin sensitivity and fertility. But to be clear, these patients were obese, and not people at a generally healthy body weight. And as mentioned, has proven remarkably therapeutic for some cancers and neurological disorders.
So, Is The Keto Diet Dangerous for Women?
All this is to say, that it’s ill-advised to think of the keto diet as a one-size-fits-all panacea, or a quick fix for weight loss; but rather as a drug with targeted applications. The ketogenic diet was developed as a treatment for epileptic patients and is remarkably therapeutic for neurological disorders, but has far-reaching implications beyond weight loss and visible abs.
Proceed with caution, especially if you are a woman under the age of 50, and particularly if you are taking hormonal birth control. Any diet modifications are best approached under the supervision of your holistic health care practitioner.