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Does Intermittent Fasting Help or Harm Your Menstrual Cycle?

Discover the truth behind this popular weight loss regime and its effects on your menstrual cycle.

Does Intermittent Fasting Help or Harm Your Menstrual Cycle?

Is intermittent fasting the latest hack to unlock optimal health through a calculated eating schedule, or is it a potentially harmful dieting regime that could throw your menstrual cycle completely out of whack? In order to finally get to the bottom of this age-old question, we’re going to deep dive into all things intermittent fasting and menstruation. 

What’s intermittent fasting?

A craze that has taken the world by storm for its digestive and weight loss benefits, intermittent fasting refers to an eating pattern that cycles between block periods of fasting and eating. Some studies show that beyond weight loss, this form of eating may help to improve brain and heart health.

Many who practice find it to be spiritually deepening, a ritual that ties us back to our ancestors. Ancient hunter-gatherers had no choice but to fast for unpredictable and varying intervals, which means our bodies should be more than equipped, or at the very least capable of adjusting, to extended periods of time without food.

Intermittent fasting is well-accompanied by many other forms of dietary fasting, including juice cleanses and water fasting, though intermittent fasting itself can be practiced through various methods:

  • The 16/8 method: Your daily eating window is kept within 8 hours, for example, from 1PM–9PM, or 11AM-7PM. This leaves a 16 hour fasting window until your next meal.
  • Eat-Stop-Eat: This involves fasting for 24 hours two to three times a week and eating regularly on the days in between.
  • The 5:2 diet: With this method, you consume only 500–600 calories on two nonconsecutive days of the week, but eat normally the other 5 days.

Intermittent fasting and menstruation

So, does intermittent fasting affect periods? It’s been suggested by professionals across the board that if you have issues with fertility, it’d be best to consider holding off on the practice. Which leads us to wonder… if fertility is something to be cautious of, what could this method of eating possibly be doing to our hormones?

The critical importance of calories to menstrual health

When curating a lifestyle conducive to a healthy menstrual cycle, caloric intake plays a very important role! This is important to remember, as you lose weight during intermittent fasting due to (surprise, surprise!) reducing your caloric intake. When it comes to regulating your hormones, there’s nothing quite as crucial as getting your daily nutritional goals met, including protein, healthy fats, and carbs.

The function of our hormones is directly influenced by nutrition, metabolism, and energy availability, and
any disruption could potentially lead to menstruation problems. Of course, if within your eating window you’re making sure to supply your body with all of its necessary calories and nutrients, you could bypass negative effects and actually aid your body in more ways than one. However, if used as the restrictive dietary regime it’s typically practiced as, the consequences could outweigh the pros.

NOTE: It’s important to consider that fasting is often practiced religiously and spiritually, including in Islam, Christianity, Judaism, and Buddhism.
And while fasting for religious purposes rather than on a timed, dietary scale is nothing to be hormonally concerned about, many don’t take the time to ask themselves “Is intermittent fasting good for hormonal imbalance?” until it may be too late.

Can fasting delay your period?

Short answer, maybe! Many gymnasts or athletes who undergo intense conditioning skip their period for months on end due to their bodies not getting the sufficient nutrients necessary to support their cycle. With this in mind, when you’re undergoing any sort of fasting regime, whether it be intermittent or a full on juice cleanse, your body could be missing out on important doses of protein necessary to keep it operating optimally.

There are a number of “intermittent fasting stopped my period” anecdotes from people globally, sharing that their period stopped when they started doing intermittent fasting and went back to its regularly scheduled programming after eating normally again. While the fasting itself wouldn’t cause amenorrhea, the absence of menstruation, your body’s subsequent lack of fats would.

What are the effects of fasting during menstruation?

When practicing intermittent fasting, you’ll most likely lose the weight it promises, but it’s important to consider at what cost. Many of those who suffer from hormonal irregularity have been known to struggle with disordered eating.

Prolonged starvation can lead to low estrogen and progesterone, often accompanied by amenorrhea. Other known hormonal consequences of irregular eating include high cortisol and low insulin, among others.

Relative to more areas than just our hormones, our bodies demand adequate amounts of food to function properly. If a body doesn't intake enough calories to support its energy needs, the reproductive system suffers and your period could be compromised. 

In that same vein, a study done in the journal Obesity concluded that
intermittent fasting may significantly lower DHEA levels, which is associated with reduced libido, vaginal dryness, and fertility issues, though that can be combated by taking it as a supplement regularly.

Once again, if you’re practicing your block eating responsibly, meeting all caloric and nutritional needs within your allotted time frame, you could potentially evade all hormonal disruption, as well as harmful or excessive weight loss.


Are there any benefits of fasting while on period?

There are many benefits to intermittent fasting, including:

  • Cellular repair
  • Reduction in oxidative stress and inflammation
  • Cancer prevention
  • Improved metabolism
  • Alzheimer’s disease prevention
  • Blood sugar levels

And in some cases, intermittent fasting can actually aid in hormonal regulation!

Insulin sensitivity has been known to improve under this method of eating, with levels of insulin dropping dramatically. Lower insulin levels make stored body fat more accessible, leading to easier weight management. While a 2005 study showed that this
improved insulin sensitivity was more common in men than women, it’s still a recorded benefit.


So what’s the verdict: is intermittent fasting good or bad?

It’s crucial to remember that we’re all different and may react to various forms of hormonal treatments in individual ways. Your body may react well to HIIT training, while another may need something more gentle, like pilates.

There’s enough evidence to make one thing twice about practicing intermittent fasting in relation to their cycle, though its benefits are inarguable. And if you’re a person who menstruates and decide you want to incorporate intermittent fasting into your routine, our best advice would be to shorten the fasting window and ease up the week before your period,
when your body is the most prone to stress. You can also eat magnesium-rich foods to help ease PMS symptoms, or incorporate supplements like FLO PMS Relief.

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