Are Low-Carb Diets Bad for Your Hair?

It’s one of the most talked about diets: low-carb.


But, are low-carb diets good for women’s health? And, can eating low-carb have a negative impact on the health of our hair?


Carbohydrates are a primary energy source for our bodies. But many people that advocate for low-carb or ketogenic (also just called ‘keto’) diets wax poetic about how harmful carbohydrates can be for health.


Although people may choose to follow these types of diets for different reasons, the main motivation that I see behind people eschewing carbohydrates is to lose weight.


While some people do lose weight following a low-carb diet, this way of eating is not for everyone and is not without its risks.


For women especially a low-carb diet may actually be harmful to your overall health and have a negative impact on hair health as well.


What is “low-carb”?


In general, a low-carb diet is one that restricts overall carbohydrate intake to below 75 grams of carbohydrates per day. A very low-carbohydrate diet may limit carbs to less than 50 grams per day.


How low-carb diets can sabotage women’s hormones


Before we talk about how low-carb diets can mess up women’s hormones, we need to learn about how stress and our hormones intersect.


Endocrine glands are responsible for producing and releasing chemical messengers called hormones. Three endocrine glands – the hypothalamus, pituitary, and adrenal glands – work closely together to regulate our stress response, immune system, digestion, and more. Because of their tight-knit relationship, we refer to them as the hypothalamic-pituitary-adrenal axis (or HPA axis, for short).


Stress activates the HPA axis and it sets off signals in our body. Because it plays a major role in shaping our overall wellness, it’s important that we understand the HPA axis’ function and learn how we can support it properly.


A balanced HPA axis is required for balanced hormones like thyroid, progesterone, DHEA, etc. And if we want a balanced HPA axis (which I know you do) then we need to uncover the sources of chronic stress that are activating it and keeping it (and our other hormones) off-tilt.


Read: Heart Rate Variability And Hair Loss


The most important thing that you need to know about chronic stress as it relates to the HPA axis is that it comes in many different forms – not just the mental or emotional stress that we typically think of (though, that can be part of it).


Here’s what we know about low-carb diets and how they affect many women: it is a source of stress.


Read that again if you have to!


That’s one of the key reasons that following a low-carb diet can lead to hormone imbalances in women.


woman laying down and covering her eyes


This may be especially important for women who are experiencing other sources of chronic stress like emotional or mental stress, blood sugar imbalances, sleep issues, hidden infections like gut dysbiosis, or a high toxic load to be mindful of. Given the especially high stress that the body is under already, adding low-carb dieting on top of all this is counterproductive at best.


Our body’s early response to stress is to increase production of hormones like cortisol. Cortisol plays many different and important roles in our body, but it’s mainly known as our “stress hormone”. When we’re faced with an acute stressor that our body needs to respond to quickly (like a hungry lion that we might have historically confronted in the wild), we need hormones like cortisol to help get our body in motion.


That important and possibly life-saving role of our stress hormone cortisol in an acute situation can have a very negative impact on our health when it remains elevated constantly due to chronic stress. Chronic stress leads to the HPA axis activation and imbalance of our hormones.


Low-carb diets have actually been shown to increase production of cortisol and push our HPA axis further out of balance. What that means is that following a low-carb diet can be a source of stress on our body.


Because our HPA axis and hormone balance is linked so closely, one of the potential consequences of women following a low-carb diet (especially over a longer period of time) is that hormone levels decrease. This is sometimes referred to as a ‘late-stage’ adaptation to on going chronic stress. But, disruptions in our hormone levels resulting from stressors can happen more quickly as well.


One symptom that many women with decreased hormone levels recognize is irregular or missing periods (a condition called amenorrhea). A study that looked at how the ketogenic diet (very low-carb) affected adolescents found that 45% of them lost their periods within 6 months.  


Low-carb diets and thyroid health


Another hormone that can be impacted by low-carb diets is thyroid hormone. Having a healthy, optimally function thyroid is so important to our overall wellness and is also helps our body grow healthy hair.


Even though our thyroid gland produces a lot more of a hormone called T4, it’s actually the activated thyroid hormone T3 that our hair health is hinged on. It’s up to special enzymes called deiodinases turn the T4 into the T3 that we need. However, there are a lot of different factors that can interrupt that conversion or even wind up deactivating thyroid hormone into something called reverse T3 (rT3).


Read: Thyroid Hormone And Your Hair


Low-carb diets can reduce our T3 levels and can also increase our rT3 levels which acts to block the remaining T3 from doing its job in our cells. Also, remember that low-carb diets increases stress on our body and ramps up production of cortisol. High cortisol levels also harm our thyroid health and hormone function, driving us further into thyroid hormone imbalance.


How many carbs should women eat?


After reading all this, you’re probably wondering: How many carbs should I be eating? Of course, determining your unique dietary needs isn’t something that I can do in this blog article. It is something that can help clients with when I work one-on-one with them. You can learn more about working with me when you book a virtual Introduction Consult.


A moderate intake of carbohydrates, which is estimated at between 75-150 grams of carbohydrates per day, may be best for most women. Some women, including athletes (and I’d definitely consider any one doing CrossFit to fall into this category) may likely require even more carbohydrates to maintain their health.


Closing thoughts on carbs


Beyond talking about the quantity of carbohydrates we eat, it’s important to be equally focused on improving the quality of the carbohydrates we eat. More refined or processed carbohydrates are less nourishing, promote inflammation, and disrupts our blood sugar which can lead to hormone imbalances. Aiming to include plenty of minimally processed, whole-food sources of carbohydrates in our diet is an important step to rebuilding and maintaining wellness.

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