Missing Your Period on a Plant-Based Diet? What You Need to Know About Functional Hypothalamic Amenorrhea
When your period disappears, it can feel confusing, worrying, and even a little isolating. The medical name for this is Functional Hypothalamic Amenorrhea (FHA). It happens when the brain essentially “switches off” reproduction because it senses the body doesn’t have enough energy or safety to sustain it.
The effects are far from invisible. Women with FHA often notice fatigue, mood changes, hair thinning, and even an increased risk of bone loss. For many, fertility concerns become very real too.
As a vegan nutritionist and naturopath, I see FHA frequently in women who come to me with diets that look wonderfully healthy on paper. That’s not because vegan or vegetarian diets are inherently problematic—they can be incredibly supportive for hormone health, fertility, and long-term disease prevention when done correctly. The issue arises when women aren’t eating enough to meet their body’s needs, often without even realising it.
The Case of the “Perfect” Vegan Diet
One of the most common things I notice in clinic is women presenting with what looks like an immaculate plant-based diet. They eat legumes, nuts, seeds, vegetables, whole grains—the picture of health.
But then I ask about quantities.
I’ll never forget one young woman who hadn’t had her period in over two years. Her blood tests showed her hormones were virtually non-existent. And it didn’t surprise me—her portions were tiny. Her “bowl” of oats was just a couple of spoonfuls, which I can assure you is not meeting anyone’s nutritional needs.
We increased her intake to a nourishing, sustainable level and I prescribed a personalised herbal formula to support her endocrine system. Within just a few weeks, she had her first period in years. The most joyous part of her story is that she went on to have a beautiful, healthy baby girl—something that would never have been possible without rebuilding her diet.
Why Plant-Based Women Can Be Vulnerable
Plant-based diets can absolutely support healthy cycles, but they do have characteristics that make some women more prone to FHA:
Low calorie density. Vegetables, legumes, and grains are filling, but not always energy-dense. Without larger portions and calorie-rich foods like nuts, avocado, tahini, or grains, intake may fall short.
High fibre satiety. Fibre is wonderful for digestion, but it can blunt appetite, leaving women under-eating without noticing.
Lifestyle overlap. Many plant-based women also practise yoga, running, or other regular exercise. Combine this with low energy intake, and the body feels it has to ration energy.
Clinical research supports this: even without weight loss, simply eating too little for the body’s needs can disrupt menstrual cycles (Loucks & Thuma, 2003). Stress and exercise add further pressure (Misra & Klibanski, 2014; De Souza & Williams, 2004).
Restoring Menstrual Health Naturally
Recovery always begins with nutrition. The body must feel safe and nourished. This means:
Eating enough calories daily.
Prioritising calorie-dense plant foods such as tahini, nuts, avocado, coconut, and Ahiflower oil.
Ensuring plant proteins like lentils, tofu, tempeh, and quinoa are part of meals every day.
Covering key nutrients such as iron, zinc, B12, iodine, and omega-3 fats from sources like flax, chia, walnuts, or Ahiflower.
Herbal medicine can also play a powerful role:
Vitex agnus-castus (Chaste Tree Berry): Known for supporting progesterone balance.
Withania somnifera (Ashwagandha): Helps calm the stress response and support nervous system resilience.
Rehmannia glutinosa: A traditional herb used to restore menstrual cycles.
In my experience, it’s the combination of a fully nourishing plant-based diet and targeted herbal support that allows the body to trust it can safely restart ovulation and menstruation.
Signs You Might Have FHA
Your period has been absent for three months or more.
You feel constantly fatigued despite sleeping well.
You recover slowly from exercise.
Libido is much lower than usual.
You’ve experienced stress fractures or unexplained bone aches.
Listening to the Body’s Wisdom
Philosopher Lao Tzu wrote: “Nature does not hurry, yet everything is accomplished.”
FHA is the body’s quiet way of saying: I need more nourishment, more rest, and more safety.
The good news? With the right nutrition and support, periods often return surprisingly quickly. A missing period isn’t just about fertility—it’s one of the most important signs of your overall health and vitality.
How I Support Women as a Vegan Nutritionist and Naturopath
If you’re plant-based and struggling with FHA—or other issues like digestive problems, fatigue, hormonal imbalances, skin challenges, or PMDD—I want you to know you don’t have to navigate it alone.
In my naturopathy practice, I work with vegans and vegetarians around the world to:
Rebuild energy and hormone health with tailored vegan nutrition plans.
Use evidence-based herbal medicine to support balance and resilience.
Address conditions like PMDD, SIBO, IBS, iron deficiency, fatigue, skin problems, and more—without giving up your plant-based values.
Your health is not about restriction or perfection—it’s about balance, nourishment, and creating a lifestyle your body can thrive on.
🌿 Learn more or book a consultation: Camilla Clare Holistic Health
References
Loucks, A. B., & Thuma, J. R. (2003). Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. Journal of Clinical Endocrinology & Metabolism, 88(1), 297–311.
Misra, M., & Klibanski, A. (2014). Endocrine consequences of anorexia nervosa. Lancet Diabetes & Endocrinology, 2(7), 581–592.
De Souza, M. J., & Williams, N. I. (2004). Physiological aspects and clinical sequelae of energy deficiency and hypoestrogenism in exercising women. Human Reproduction Update, 10(5), 433–448.