Studies show that low-carb diets can cause weight loss and improve metabolic health.
However, even though low-carb diets are great for some people, they may cause problems for others.
For example, following a very low-carb diet for a long time may disrupt hormones in some women.
Eating too few carbs has been associated with disruptions to the menstrual cycle, fertility problems and poor sleep quality.
It’s also been linked to poor bone health, anxiety and depression. Some women even report weight loss resistance or weight gain.
This article explores how low-carb diets may affect women’s hormones.
Low-Carb and Low-Calorie Diets May Affect Women’s Adrenals
Your hormones are regulated by three major glands:
Hypothalamus: located in the brain.
Pituitary: located in the brain.
Adrenals: located at the top of the kidneys.
All three glands interact in complex ways to keep your hormones in balance. This is known as the hypothalamic-pituitary-adrenal (HPA) axis.
The HPA axis is responsible for regulating your stress levels, mood, emotions, digestion, immune system, sex drive, metabolism, energy levels and more.
The glands are sensitive to things like calorie intake, stress and exercise levels.
Concerned Young Woman
Long-term stress can cause you to overproduce the hormones cortisol and norepinephrine, creating an imbalance that increases pressure on the hypothalamus, pituitary and adrenal glands.
This ongoing pressure may eventually lead to HPA axis dysfunction, sometimes controversially referred to as “adrenal fatigue”.
Symptoms include fatigue, a weakened immune system and greater risk of long-term health problems such as hypothyroidism, inflammation, diabetes and mood disorders.
Many sources suggest that a diet too low in calories or carbs can also act as a stressor, causing HPA dysfunction.
In addition, some evidence suggests that low-carb diets can cause increased production of cortisol (“the stress hormone”), making the problem worse.
One study found that, regardless of weight loss, a low-carb diet increased cortisol levels compared to a moderate-fat, moderate-carb diet.
Bottom Line: Eating too few carbs or calories and experiencing chronic stress may disrupt the HPA axis, causing hormonal problems.
A Low-Carb Diet May Cause Irregular Menstrual Cycles or Amenorrhea in Some Women
Red Set of Scales Weighing Broccoli
If you don’t eat enough carbs, you may experience irregular menstrual cycles or amenorrhea.
Amenorrhea is defined as a woman’s menstrual cycle being absent for 3 months or more.
The most common cause of amenorrhea is hypothalamic amenorrhea, caused by too few calories, too few carbs, weight loss, stress or too much exercise.
Amenorrhea occurs due to the drop in levels of many different hormones, such as gonadotropin-releasing hormone (GnRH), which starts the menstrual cycle.
This results in a domino effect, causing a drop in the levels of other hormones such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen, progesterone and testosterone.
These changes can slow some functions in the hypothalamus, the region of the brain responsible for hormone release.
Low levels of leptin, a hormone produced by fat cells, is another potential cause of amenorrhea and irregular menstruation. Evidence suggests that women need a certain level of leptin to maintain normal menstrual function.
If your carb or calorie consumption is too low, it can suppress your leptin levels and interfere with leptin’s ability to regulate your reproductive hormones. This is particularly true for underweight or lean women on a low-carb diet.
However, evidence on amenorrhea on low-carb diets is scarce. Studies that report amenorrhea as a side effect were usually only done in women following a predominately low-carb diet for a long period of time.
One study followed 45 teenage girls on a ketogenic (very low-carb diet) diet for 6 months. 45% experienced menstrual problems and 6 experienced amenorrhea.