Is Eating Too Low Carb Affecting Your Hormones?

Liz Riesen, RD
3 days ago
3 min read

Keto may still be popular—but that doesn’t mean it’s right for you. In fact, if you’re a woman struggling with fatigue, bloating, anxiety, weight fluctuations, or missing periods…a diet that is too restrictive on carbs could be doing more harm than good.

Let's talk about why.

bowl of oatmeal with blueberries and almonds

Is Eating Too Low Carb Causing Hormone Imbalance?

Women’s hormones are especially sensitive to calorie and carb restriction. Carbohydrates play a critical role in hormone production, blood sugar regulation, and even ovulation. When you cut carbs too low, it can increase cortisol (your stress hormone), suppress your thyroid, and even lead to irregular or missing periods.

I see so many women in their 30s and 40s who cut carbs or even try a strict keto diet to “fix” their metabolism—but instead end up exhausted, anxious, foggy, and more inflamed than before.

Why does this happen? Your brain needs glucose to feel safe. Without it, your body goes into stress mode and cortisol spikes. This might show as anxious, poor sleep, low energy, hair loss, mood swings, or a metabolism that feels completely stalled out.

When cortisol levels remain elevated it sends the body into HPA dysfunction. This response tells the body to go into "fat storage mode" - the body doesn't know how long it will be in a high stress state so it wants to conserve and store as much excess energy as possible (opposite of what you want).

This is why women who stop keto because it is not sustainable, often see the weight come back on and then some!

Is The Keto Diet Right for PCOS or Insulin Resistance?

While it's true that a strict low carb or keto diet can lower insulin levels, it's important to be working with a dietitian like myself to personalize your macros and sync your diet with your menstrual cycle so that we don't disrupt natural hormone balance.

Insulin is required for the conversion of the inactive thyroid hormone T4, into the active thyroid hormone T3. When insulin levels drop too fast or for too long it can lead to low T3 levels in the body and hypothyroid symptoms, including:

Fatigue.
Weight gain.
A puffy face.
Trouble tolerating cold.
Joint and muscle pain.
Constipation.
Dry skin.
Dry, thinning hair.
to name a few...

When working with a client with PCOS or insulin resistance, I will recommend a moderately low carb diet tailored to each woman. There should always be a strong emphasis on complex carbohydrates, resistant starch, fiber, and polyphenols to support a healthy microbiome and metabolism.

What's the best diet for women and hormone balance?

The best diet is one that is personalized for you and your body. Your body type, age, genetics, and preferences should all be included for an ideal diet.

However I won't leave you with just that. The best diet starts with ingredients, so choosing whole foods as much as possible and majority plants. This doesn't mean don't eat animal proteins - but it means you should have a large variety of plants in your diet. Plants include vegetables, fruits, nuts, seeds, legumes, beans, and whole grains.

A woman can absolutely be gluten-free or even grain-free and have a healthy, balanced diet. Same goes for a woman who needs to avoid beans and legumes. Or a woman who prefers not to eat animal protein. For everyone, it is important to know the essential nutrients you need and in what balance so that you don't end up with nutrient deficiencies.

So instead of chasing extreme diets like keto, focus on hormone-supporting nutrition:

✔️ Slow carbs (sweet potatoes, root veggies, beans, fruits, whole grains)

✔️ High-quality protein

✔️ Healthy fats (plenty of olive oil)

✔️ Fiber and colorful veggies

These foods help stabilize your blood sugar, reduce inflammation, and support happy hormones.

As a Hormone Health Dietitian, I’m here to remind you: If your diet is causing burnout, it’s not working for you.

Want to Go Deeper?

If you suspect your hormones are out of sync, personalized nutrition and functional hormone testing can uncover what’s really going on. I offer 1:1 consultations and a comprehensive hormone testing package that dives into cortisol, estrogen, progesterone, organic acids, inflammatory markers, and more.

Link to My Foundations of Hormone Balance Program

Link to Comprehensive Hormone Testing Package