Intermittent Fasting for Women: A Smarter Approach During Perimenopause
If you’ve spent any time on social media lately, you’ve probably heard people talking about intermittent fasting. Some swear by 16:8, while others complete 24-hour or even 48-hour fasts.
But here’s what many people don’t tell you: women aren’t small men.
Our hormones change throughout the month, and during perimenopause those changes become even more unpredictable. Instead of following the exact same fasting schedule every day, learning to work with your hormones can make fasting far more effective—and much easier on your body.
Let’s explore why intermittent fasting can be such a powerful tool for women, and how to do it in a way that supports your hormones rather than stressing them.
Why Intermittent Fasting Can Be So Beneficial During Perimenopause
As estrogen begins to fluctuate in your late 30s and 40s, many women notice changes that seem to happen almost overnight.
You may experience:
- Weight gain around the stomach
- Increased cravings
- Brain fog
- Fatigue
- Insulin resistance
- Higher blood sugar
- Difficulty losing weight despite eating well
- More inflammation
One of the biggest reasons for these changes is declining insulin sensitivity.
Every time we eat, our body releases insulin to move glucose into our cells. During perimenopause, our cells often become less responsive to insulin, meaning our body produces more of it.
High insulin levels encourage fat storage, especially around the abdomen.
Intermittent fasting simply gives insulin a chance to come back down.
When insulin stays lower for longer periods, the body becomes much better at burning stored fat for energy.
Benefits of Intermittent Fasting for Women
When done correctly, intermittent fasting may help:
✓ Improve insulin sensitivity
✓ Support healthy weight management
✓ Reduce inflammation
✓ Encourage fat burning
✓ Improve metabolic flexibility
✓ Stabilise energy levels
✓ Reduce sugar cravings
✓ Support healthy cholesterol levels
✓ Improve mental clarity
✓ Give the digestive system time to rest
Many women also notice they feel less bloated and have more consistent energy throughout the day.
The Different Types of Fasting
12-Hour Fast
Perfect for beginners.
Example:
Finish dinner at 7 pm.
Eat breakfast at 7 am.
Benefits:
- Gentle on hormones
- Supports blood sugar
- Easy to maintain
- Great starting point
14:10 Fast
Fast for 14 hours and eat within a 10-hour window.
Example:
Dinner at 7 pm.
Breakfast at 9 am.
Benefits:
- Improves insulin sensitivity
- Helps reduce snacking
- Supports digestion
- Easy to fit into daily life
16:8 Fast
Probably the most popular fasting schedule.
Fast for 16 hours.
Eat within an 8-hour window.
Example:
12 pm Lunch
3 pm Snack
6:30 pm Dinner
Benefits:
- Encourages fat burning
- May improve blood sugar control
- Can help reduce cravings
- Supports healthy weight management
- Sustainable for many women
For many women in perimenopause, this is the “sweet spot.”
18:6 Fast
A slightly longer version of 16:8.
Benefits include:
- Greater metabolic flexibility
- Longer period of lower insulin
- More time for fat burning
This isn’t necessary every day but can be used occasionally if it feels good for your body.
24-Hour Fast
Often called “Eat Stop Eat.”
For example:
Dinner Monday 7 pm
Next meal Tuesday 7 pm
Potential benefits:
- Longer reduction in insulin
- Encourages fat burning
- May support cellular clean-up processes
- Gives digestion a longer rest
For many healthy women, this is something that may be done occasionally rather than every week. It’s important to stay hydrated and stop if you feel unwell.
36-48 Hour Fast
Longer fasts are becoming increasingly popular, but they aren’t suitable for everyone.
Potential benefits being researched include:
- Greater metabolic switching from glucose to fat
- Increased autophagy (the body’s cellular recycling process), though most human evidence is still emerging
- Extended digestive rest
However, longer fasts also place more stress on the body and may not be appropriate during times of high stress, poor sleep, illness, pregnancy, breastfeeding, or if you have certain medical conditions. Women with a history of eating disorders should avoid fasting unless under medical supervision.
Always speak with your healthcare professional before attempting prolonged fasts.
Fasting Around Your Menstrual Cycle
One of the biggest mistakes women make is fasting exactly the same way every single day.
Our hormones aren’t the same every week.
Menstrual Phase (Days 1-5)
Your body is already working hard.
Gentle fasting works best.
Recommended:
12-14 hours
Focus on:
Iron-rich foods
Bone broth
Hydration
Sleep
Follicular Phase (Days 6-13)
Energy begins increasing.
Estrogen rises.
Your body generally handles fasting well during this phase.
Great time for:
16:8 fasting
Strength training
Higher protein intake
Ovulation (Around Day 14)
Many women feel their strongest.
A great time for:
16-18 hour fasts if they feel good
Resistance training
Nutritious whole foods
Luteal Phase (Days 15-28)
Progesterone rises.
Your metabolism naturally increases and many women feel hungrier.
This is usually the time to back off fasting.
Instead choose:
12-14 hour overnight fasts
More healthy carbohydrates
Magnesium-rich foods
Walking
Yoga
Extra sleep
Listening to your body during this phase may help reduce stress and support hormone balance.
What If You’re in Perimenopause?
Many women no longer have predictable 28-day cycles.
Instead of following the calendar, pay attention to your body.
On days when you’re:
- Sleeping well
- Feeling energised
- Exercising comfortably
You may find a 14-16 hour fast feels manageable.
On days when you’re:
- Exhausted
- Highly stressed
- Waking at 3 am
- Feeling unusually hungry
- Recovering from illness
A shorter overnight fast and nourishing meals may be the better choice.
Flexibility is often more sustainable than rigid rules.
Tips for Successful Fasting
Drink plenty of water.
Prioritise protein at each meal.
Eat enough overall—fasting isn’t about undereating.
Include healthy fats to help keep you satisfied.
Lift weights a few times a week to protect muscle mass.
Manage stress and aim for quality sleep.
Break your fast with a balanced meal rather than ultra-processed foods.
Final Thoughts
Intermittent fasting isn’t about depriving yourself—it’s about giving your body periods of rest between meals and supporting healthy metabolic function.
For women in perimenopause, the goal isn’t to fast harder. It’s to fast smarter.
By adjusting your fasting routine to your hormones, your energy levels, and your lifestyle, you can enjoy many of the benefits of intermittent fasting while supporting your overall wellbeing.
As always, if you have diabetes, take medications that affect blood sugar, are pregnant or breastfeeding, or have a history of eating disorders, speak with your healthcare provider before starting intermittent fasting.
Your body is constantly changing through perimenopause. Learning to work with those changes, rather than against them, can make all the difference.
Heartcore Wellness 