Benefits, Fasting Timelines & How to Break Your Fast Properly
Intermittent fasting has become one of the most popular wellness practices for improving energy, supporting healthy blood sugar levels and helping the body become more metabolically flexible.
For women—especially during perimenopause—fasting can be a powerful tool when done correctly. The key isn’t simply how long you fast, but also how you break your fast afterwards.
Here’s a simple guide to the most common fasting lengths, the benefits of each, and the best foods to eat when it’s time to refuel.
Before You Begin…
Women don’t always respond to fasting the same way men do.
If you’re in your reproductive years, pregnant, breastfeeding, underweight, have a history of eating disorders, or take medications that affect blood sugar, speak with your healthcare professional before trying fasting.
During perimenopause, shorter fasts (around 12–16 hours) often work well, while longer fasts are usually best done only occasionally.
13–15 Hour Fast
The Perfect Everyday Fast
This is one of the easiest fasting windows to maintain.
Example:
- Finish dinner at 7 pm
- Eat breakfast at 9–10 am
Potential Benefits
✔ Gives your digestive system a rest
✔ Supports healthy insulin sensitivity
✔ May encourage gentle fat burning
✔ Can improve energy and focus
✔ Fits easily into everyday life
Best Way to Break It
Focus on a balanced meal containing:
- Protein
- Healthy fats
- Fibre
- Colourful vegetables
Example:
- Eggs
- Avocado
- Sourdough or sweet potato
- Spinach
16–17 Hour Fast
A Popular Intermittent Fasting Window
Many people choose this fasting length several times each week.
Research suggests that fasting beyond around 16 hours may begin to activate cellular maintenance processes such as autophagy, although the timing varies between individuals and isn’t guaranteed.
Possible Benefits
✔ Improved metabolic flexibility
✔ Better blood sugar control
✔ Increased ketone production
✔ May support cellular repair processes
✔ Improved mental clarity
Best Way to Break It
Choose:
✔ Protein
✔ Healthy fats
✔ Vegetables
Examples
- Grilled chicken
- Eggs
- Salmon
- Greek yoghurt
- Cottage cheese
24 Hour Fast
Giving Your Digestive System a Reset
A 24-hour fast should be done occasionally rather than every day.
Many people find it leaves them feeling lighter and more mindful about eating.
Potential Benefits
✔ Rest for the digestive system
✔ Improved insulin sensitivity
✔ Encourages fat burning
✔ May support gut health when followed by nutritious foods
How to Break a 24-Hour Fast
Step 1 (Wait 20–30 minutes)
Bone broth
Why?
Bone broth is gentle on the stomach and contains amino acids such as glycine and collagen that support the gut lining.
Step 2
Fermented foods
Examples:
- Sauerkraut
- Kimchi
- Plain yoghurt
- Kefir
These help introduce beneficial bacteria to the gut.
Step 3
Cooked vegetables
Choose easy-to-digest vegetables such as:
- Pumpkin
- Zucchini
- Carrots
- Spinach
- Broccoli
These provide fibre to nourish your gut microbiome.
Step 4
Protein
Finish with a protein-rich meal.
Examples:
- Chicken
- Fish
- Eggs
- Tofu
- Lean beef
36 Hour Fast
This longer fast should only be attempted if you already have experience with intermittent fasting.
Possible Benefits
✔ Increased fat burning
✔ Lower insulin levels
✔ Greater metabolic flexibility
✔ May promote cellular recycling processes
Break this fast the same way as a 24-hour fast:
- Bone broth
- Fermented foods
- Steamed vegetables
- Protein
Take your time eating and stop when comfortably full.
48 Hour Fast
A 48-hour fast is considered an extended fast and should only be done occasionally, if at all, under appropriate guidance.
Some people report improved mental clarity, but scientific evidence for specific “dopamine reset” effects is limited.
Break it gently:
- Bone broth
- Fermented foods
- Soft vegetables
- Protein
Avoid jumping straight into heavy meals or large portions.
72 Hour Fast
This is an advanced fast and isn’t necessary for most people to experience the benefits of intermittent fasting.
Some research suggests extended fasting may stimulate cellular repair processes, but more human research is needed to understand the exact effects.
If attempting a fast of this length, it’s wise to discuss it with a healthcare professional.
Break it slowly over several hours:
Bone broth → Fermented foods → Steamed vegetables → Protein
Short Fast? Break It Based on Your Goal
Want to Stay Full Longer?
Choose healthy fats
Examples:
- Avocado
- Nuts
- Nut butter
- Extra virgin olive oil
Building Muscle?
Break your fast with:
- Eggs
- Chicken
- Steak
- Fish
- Greek yoghurt
Aim for around 25–30 g of protein in your first meal.
Need More Energy?
Choose:
- Bone broth
- A protein smoothie
- Greek yoghurt
- Cottage cheese
Supporting Gut Health?
Include fermented foods:
- Kimchi
- Sauerkraut
- Kefir
- Natural yoghurt
Which Fast Is Best for Women?
For most women, especially during perimenopause:
⭐ 13–15 hours is excellent for everyday health.
⭐⭐ 16–17 hours can be done a few times per week to support metabolic health.
⭐⭐⭐ 24 hours may be appropriate occasionally for experienced fasters.
Longer fasts (36–72 hours) should be approached with caution, as they aren’t necessary for good health and may not be suitable for everyone.
Final Thoughts
Intermittent fasting isn’t about eating less—it’s about giving your body time to rest between meals while still nourishing it well when you eat.
The best fasting routine is one that fits your lifestyle, supports your energy levels and leaves you feeling your best. Pair fasting with whole foods, regular movement, good sleep and stress management, and you’ll build a sustainable routine that supports long-term health.
one for women in perimenopause, one for 24-hour fasting, and one for foods to break a fast.
Heartcore Wellness 