How Fasting Can Help (or Hurt) Your Hormones

Fasting is trending but if you’re trying to conceive, the wrong approach can backfire.

You’ve seen it everywhere intermittent fasting is hailed as the secret to weight loss, mental clarity, and hormone health. But here’s what most of the internet doesn’t tell you: women’s bodies are uniquely wired, especially when it comes to our hormones and fertility.

At RESTORED HEALTH, we help women and couples restore hormone balance and decode their body’s signals for natural fertility. And when it comes to fasting, one-size-fits-all advice can do more harm than good.

In this post, you’ll learn:

• How fasting actually impacts female hormones

• The right way to fast, based on your cycle

• When your body is telling you to stop fasting altogether

  
  

Let’s break it down…

1. How Fasting Affects Female Hormones

Men and postmenopausal women can often fast daily without much issue. But in cycling women especially those trying to conceive fasting impacts key hormones like:

• Cortisol (stress hormone): Extended fasts can spike cortisol, which suppresses ovulation.

• Insulin: Short-term fasting can improve insulin sensitivity—great for PCOS or blood sugar issues.

• Estrogen & Progesterone: These fluctuate based on your cycle, and fasting can delay or dull their natural rise and fall.

  
  

The takeaway? Fasting affects hormones—and depending on timing, it can either support or sabotage your fertility.

2. The Right Way to Fast (Based on Your Cycle)

If you want to fast and support your fertility, cycle syncing is key. Here’s how to tailor your fasting around your hormonal phases:

Follicular Phase (Days 1–14)

• Your body is naturally more insulin-sensitive

• A short fast (12–14 hours overnight) may be beneficial

• Focus on blood sugar stability and light movement

  
  

Ovulation (Around Day 14)

• Estrogen peaks—your body needs fuel

• Avoid long fasts; aim for nutrient-rich meals to support egg quality and energy

Luteal Phase (Days 15–28)

• Progesterone rises—you need more calories, not less

• Longer fasts can increase cortisol and disrupt implantation

• Shift to nourishing, grounding foods and reduce fasting time

3. Signs Your Body Needs More Nourishment

If your fasting routine is backfiring, your body will tell you. Here are some red flags:

• Worsening PMS or irregular cycles

• Trouble sleeping, especially early waking

• Mood swings, anxiety, or brain fog

• Feeling cold all the time or loss of libido

• Increased sugar or caffeine cravings

• Lack of ovulation or light/short periods

  
  

If you're experiencing these symptoms, it’s time to pause and rebuild safety and nourishment in the body. Your fertility depends on it.

Additional Tips & Common Mistakes to Avoid

✅ Keep fasting under 14 hours if you’re in your fertile years 

❌ Avoid fasting during your luteal phase (after ovulation)—your body needs more energy 

✅ Eat enough calories overall—fasting isn’t about under-eating 

❌ Don’t copy what works for men or influencers—your hormonal needs are unique 

✅ Pair fasting with cycle tracking and symptom awareness

Fasting Isn’t One-Size-Fits-All Especially for Women

The truth is, fasting can be a powerful tool—but only when done with intention, body awareness, and hormonal insight. If you're trying to conceive or restore hormonal balance, your approach matters more than ever.

At RESTORED HEALTH, we help women navigate the fine line between healthy strategies and hormone stressors so you can stop guessing, and start healing.