How intermittent fasting could be causing your missing period or delaying your recovery

Intermittent fasting (IF) has become all the rage in recent months and years. We’re constantly hearing about the many, many benefits it promises… but despite all the hype, the actual evidence surrounding IF is negligible. Not only have most studies been conducted on animals, but emerging research suggests it might actually have some negative impacts – particularly for women!

What is intermittent fasting?

Intermittent fasting is the cycling between prolonged periods of fasting, or going without food, alternating with periods during which you eat “normally”. The most common form of IF is the 16:8, where you fast for 16 hours of the day (including while you sleep), and then eat all your meals for the day within an 8-hour window. There are plenty of other variations too, including some which require entire days of limiting or reducing your energy intake.

So can you adhere to IF while you’re working on recovering from disordered eating, hypothalamic amenorrhea or an eating disorder? Let’s dive into the areas of recovery which are most significantly impacted by fasting.

The impact of intermittent fasting on your hormones.

Much of the emerging research around the potential of IF to be harmful to women centres around its ability to wreak havoc on your hormones. Think about it logically… If your body is essentially in a starving state for 16 hours of the day, it perceives this as a significant stress. It doesn’t know when it will be fed again, so it increases production of one of your stress hormones, cortisol, and sends you into a “fight or flight” state. Simultaneously, it lowers oestrogen production and other hormones which are regulated by brain glucose.

This is because, if your brain isn’t getting a reliable supply of glucose from your food, your body will compensate in other ways – which often aren’t in the best interests of your general health. Long periods spent in a state of stress and energy deficiency can often lead to hormonal fluctuations and imbalances especially in women, which we know is very problematic in recovery.

Part of recovery centres around re-feeding your body, and restoring it to a state of safety, where it feels nourished and can rely on the fact it will receive regular, satisfying meals and snacks. This tells your body it no longer needs to conserve energy and remain in a stressed state, allowing it to resume functions like menstruation. So when you’re actively adding stress to your body and hormones by fasting, this interferes with all the other work you’re doing in recovery. All the effort you’re putting into eating enough, being consistent, and preparing nourishing, energy-dense meals and snacks, is being somewhat negated by fasting.

You’ll experience an energy deficit during the day.

Studies have also shown that the less time you can spend in an energy deficit throughout the day, the “safer” your body feels, supporting your efforts to recover and restore your body to optimal health and function.

For example, if you wake up and head to the gym before eating, you’re putting yourself straight into an energy debt. This means your body immediately experiences physical stress, again impacting your hormones and your production of cortisol.

Compare this scenario to one where you eat breakfast before heading to the gym… Even if you achieved the exact same energy intake across the day as you did in the previous example, you’re spending less time in an energy deficit. You’re fueling your body before you use up your energy stores, so your body feels more safe, and is secure in the knowledge that it can rely on a nourishing, satisfying meal and energy supply being provided as needed.

If you’re following a fasting pattern, this makes it extremely difficult to be in a state of energy surplus for enough time throughout the day. Even if you’re getting enough energy by the end of the day, chances are your body is still experiencing physical stress and the repercussions of this during the times you’re fasting, making recovery more difficult and prolonged.

The timing of your meals matters in recovery.

Similarly, when you eat your meals and snacks is actually super important when you’re in recovery.

Ideally, you want to be eating a good, nourishing breakfast within an hour of waking – and definitely before you do any movement or exercise! You should also ensure you’re eating meals and snacks throughout the day, and even potentially add in a snack before you head to bed to give your body enough energy for the repair it undergoes as you sleep.

Hear more about why meal timing matters in recovery in this podcast episode.

If you’re meeting all these targets, it doesn’t really leave room for fasting… Essentially, you’re working to restore your body to health, which requires re-feeding it after long periods of malnourishment and deprivation.

To do so, you really need to be providing it with adequate energy all day, every day. So fasting doesn’t fit with this key focus of recovery.

Fasting makes it difficult to get enough energy.

Following on from this, in recovery you should be aiming to eat at least 2,500 calories each day – even if you’re completely resting from movement. This is essential for allowing your body to restore itself, and feel safe enough to resume critical functions such as menstruation and ovulation.

If you’re fasting for 16 hours out of 24, your feeding window is obviously very restricted. This can make it extremely challenging to pack in those 2,500 calories – especially if you’re already struggling to restore your hunger cues.

If you find it difficult to get enough energy even without restricted timings, due to feeling excessively full or bloated, or simply not experiencing hunger, it becomes far more difficult when you have to do so in an even shorter window of time.

It’s not practical, realistic or necessary to limit the window of opportunity you give yourself to nourish and restore your body – especially when you’re focusing on recovering from an eating disorder, hypothalamic amenorrhea or disordered eating.

It can worsen your disordered behaviours.

Intermittent fasting also really perpetuates the restrictive, fearful mentality around food and eating which you’re working so hard to overcome in recovery. It contributes ot disordered patterns and rules around food, and while it may not seem as “unhealthy” or “dangerous” as some behaviours you’ve exhibited in the past, it’s like a wolf in sheep’s clothing… It seems innocent enough, but if you’re truly honest with yourself, you’re allowing yourself to continue limiting yourself to strict rules around your eating behaviours and your life in general.

Not only does IF interfere with your social life, by causing you to say no to meals and activities outside of your “eating window”, it’s also just another rigid rule you’re enforcing upon yourself. And both these ideas are contrary to what you’re working so hard for on your recovery journey! So don’t be fooled, and don’t lie to yourself. IF isn’t “healthy”, it’s simply another outlet for your disordered behaviours to manifest and continue to control you.

Take control back, and remember what you’re working for in recovery. Don’t undo all that hard work and commitment by adopting another (arguably) diet in disguise!

Want some support to help you overcome your food rules and restrictions, and finally achieve full recovery? Sign up to our 1:1 coaching program today, so we can help you improve your relationship with food, exercise and your body, and achieve lasting behavioural change, so you can reclaim your life and freedom!