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Is It Safe To Fast On Your Period? What An MD Wants Women To Know

Author:

Kim Foster, MD

March 11, 2024

Doctor & health coach

By Kim Foster, MD

Doctor & health coach

Dr. Kim Foster is an MD-turned-coach and wellness expert who helps high-achieving women master the art of living well.

Woman having breakfast with friends looking at plate

Image by Pedro Merino / Stocksy

March 11, 2024

Intermittent fasting has surged in popularity as a way to reduce inflammation 1, improve metabolic health 2, and more. But is it suitable for women?

As an M.D.-turned-coach with 20 years' experience as a family doctor, I've been hearing a lot of questions recently along the lines of, Do women need to fast differently than men? Is fasting safe during your period? Should I adjust my fasting throughout my cycle?

I've noticed that many women I come in contact with are interested in trying intermittent fasting but hesitate because they're worried about doing it "wrong." So, let's clear up the confusion.

First, research shows that intermittent fasting can benefit people of any gender. That said, for many women, it does require a tailored approach based on their cycle. Here are the basics of what you need to know, plus some simple guidance for getting started.

What to know about your luteal phase

The luteal phase happens during the second half of your menstrual cycle, just after ovulation.

During this phase, your body gets prepped for the possibility of pregnancy. Your ovaries start producing more progesterone, which thickens the lining of your uterus in case a fertilized egg decides to make itself at home.

But if pregnancy doesn't happen, your hormone levels start to drop. That's when those pre-period symptoms, like mood swings, bloating, and maybe even some chocolate cravings, can occur.

So, how can the luteal phase impact the way your body responds to intermittent fasting? A few ways:

Hunger and Cravings: Many women experience cravings during the luteal phase, particularly for carbs and sweets. This can make some types of fasting more challenging, as your desire to eat during certain times may be stronger.
Energy Levels: Some women feel more fatigued or lethargic during part of their luteal phase, making it harder to stick to a fasting routine, especially if you have a very active or demanding schedule.
Mood and Emotions: During the luteal phase, some women experience mood swings, irritability, or anxiety. These emotional factors can affect your ability to stay on track with fasting.
Fluid Retention and Bloating: Some women experience water retention and bloating during the luteal phase, which can affect body weight and influence your perceived progress if weight loss is one of your fasting goals.

How to account for hormonal changes while fasting

Given all that, what's the best way to approach fasting if you're a menstruating woman? Here are my top tips:

Start slowly

Begin with shorter fasting periods, like a 12:12 schedule, and gradually increase fasting duration as your body adjusts. You may eventually work up to closer to a 16:8 schedule (an eight-hour eating window and a 16-hour fasting window), but there's no rule saying you have to.

Track your cycle

Pay attention to your cycle, and monitor how fasting affects your mood, energy levels, and hunger throughout each phase. Consider using an app to track your cycle.

Stay flexible

Be prepared for flexibility with your fasting schedule during certain phases, particularly during the luteal phase and during menstruation. If you're sensitive to hormonal fluctuations and experience a lot of hunger, cravings, mood, or energy variability, then consider a more relaxed approach or shorter fasting windows during this time.

Listen to your body & watch out for red flags

Pay attention to hunger cues, energy, and any discomfort. If fasting feels overly challenging or unsustainable, adjust your approach or seek guidance from a health care professional. Pay attention to warning signs such as extreme fatigue, dizziness, headaches, or irregular menstrual cycles.

If you have underlying medical conditions, are pregnant or breastfeeding, or experience persistent adverse effects while fasting, consult a health care provider for personalized guidance and support.

Prioritize nutrient-dense foods

Don't ignore the importance of what you're eating when you're not fasting. Focus on whole, nutrient-rich foods to support overall health and ensure adequate nutrient intake. Protein is especially important.

Stay hydrated

Drink plenty of water during fasting periods to stay hydrated and support digestion, energy levels, and overall well-being.

Monitor progress and make adjustments

Keep track of your progress, including changes in energy levels, weight, and menstrual cycle regularity. Use this information to make adjustments to your fasting routine as needed.

Practice self-compassion

Be kind to yourself and prioritize self-care throughout the fasting journey. If fasting becomes overly stressful or negatively impacts your well-being, it's OK to take a step back or explore other options. Fasting is not the only way to reach your health goals.

Honor your individual needs

It's a good idea to experiment with different fasting schedules to find what works best for your body and lifestyle. Because here's the thing: Not everybody's menstrual cycle is the same. Some women need to make major adjustments to their fasting schedules during their luteal phase, but not everyone does. Some of us can get away with only minor tweaks. We're each unique!

The takeaway

You don't need to be afraid to try fasting because you've heard it's more complicated for women. I'm not saying fasting is for everyone (it's not), but the key is to listen to your body, get familiar with your own monthly rhythms, and be flexible with your fasting schedule as needed. I hope this empowers you to experiment and find what works best for you.