Should you be fasting for 36 hours?

Fasting is back in the headlines, but should you be thinking about a 36 hour fast? My honest answer, as a female, no. Here’s why… If you push your body into a long 2 day fasted state, you’re shifting your body’s fuel source away from ATP via glucose towards fat. This is tiptoeing towards something called a ketogenic state. But 36 hours is not long enough to actually push your body into ketosis – instead you are dancing around it.

Shifting in and out of these states has the potential to promote a biological agility to adapt to different metabolic states but it could end up being counterproductive for some, leading to an intolerance to glucose. More research is needed to back up bold claims that 36 hours of fasting a week is beneficial. And what little research we have is mostly on animals and young males. So I beg to question its safely for the female hormonal system, which is biologically very different and women respond differently to fasting.

What I believe this 36hr trend is able to provide for high achieving CEOs and men in powerful positions is the ability to use this framework like a uniform. If your energy is not being taken up deciding what it is you are eating for breakfast, lunch and dinner you are able to keep your focus on other things – like running the country. It’s the opposite to tab culture by removing choice and everyday decisions. A little like wearing a uniform, famed by Steve Jobs. Steve Jobs believed that the less time he spent making decisions, the more time and energy he had for the important things. Why waste your time on nutritious lunch?

So are the benefits of a 36 hour weekly fast metabolic agility, or are they borne from the benefits of removing mundane decisions from your day to create the illusion of productivity and razor focus? I think the latter.

What are the negatives and the impact on your hormones?

Where there comes intense restriction, there can come a lack of control when you are in window of eating. Not always, but you do open the door to binge eating. We all have a rebellious side and this can kick in.

A pretty major point to raise is that the body needs the raw materials to thrive, so you are restricting access to vital nutrients for a large part of your week. And it would make for a pretty boring dinner with a partner in the evening…air! Where is the joy in that?

As a female, one note that is important to make in terms of your hormonal health is your circadian rhythm. When you fast, you may be going against your natural eating windows, which could drive issues with your metabolism and secretion of hormones. More research is needed on the impact that fasting could have on hormonal health and the body clock of your hormones. Limited food availability in specific periods stimulates an organism to alter the level and frequency of hormone secretion, so what are the long-term implications on the female hormonal cycle? I would highlight again the impact on circadian rhythm and that it could drive hormonal dysfunction with your oestrogen levels.

 Fasting and exercising in the morning in a fasted state could also drive elevated cortisol, which can have systemic repercussions.

If you’re going to fast, is there a limit on how long you should do it for?

What I am a fan off is fasting in between meals – a fab breakfast, then lunch, then dinner with no snacking in between. Not snacking in-between meals is still a form of IF. I’m a big fan of this style of eating (if it suits the client), as the positive impact on insulin sensitivity can be great for creating a happier environment for your hormones.

 What we can do here is allow the body to have a rest at sending insulin out to deal with snacks in between meals. When there is more circulating insulin we can hinder the use of glucose, making it hard to actually use the energy that we are eating plus drive up uric acid which can increase blood pressure. Sticking to three main meals can avoid the constant deluge of insulin around the body, which can drive insulin resistance, which could then dramatically drive weight gain, hormonal dysfunction and things like type 2 diabetes risk.

 And for women, insulin is more of a morning person, so if you wanted to enjoy a longer fast overnight I would suggest an earlier dinner around 7pm and break it about 1 hour after waking.

Are there certain people who should not be fasting?

If we were to see hormonal dysregulation, in particular conditions like PCOS, one would need to be careful around long morning fasting and high-intensity exercise when in a fasted state — both of these have the potential to drive elevated cortisol, which can then drive elevated testosterone and insulin resistance. Plus, there is a window of vulnerability for women with endocrine disorders like PCOS and risk of disordered eating.

I would avoid fasting if you were TTC and most definitely when pregnant and when breastfeeding. You could be missing out of windows of opportunities to maximise important nutrients that are essential for hormone health, fertility, and reproductive functions.

If I wanted to give fasting a go, what should I try?

What I am a fan of is fasting in between meals – a fab breakfast, then lunch, then dinner with no snacking in between. Not snacking in-between meals is still a form of IF. I’m a big fan of this style of eating (if it suits the client), as the positive impact on insulin sensitivity can be great for creating a happier environment for your hormones.

What we can do here is allow the body to have a rest at sending insulin out to deal with snacks in between meals. When there is more circulating insulin we can hinder the use of glucose, making it hard to actually use the energy that we are eating plus drive up uric acid which can increase blood pressure. Sticking to three main meals can avoid the constant deluge of insulin around the body, which can drive insulin resistance, which could then dramatically drive weight gain, hormonal dysfunction and things like type 2 diabetes risk.

And for women, insulin is more of a morning person, so if you wanted to enjoy a longer fast overnight I would suggest an earlier dinner around 7pm.

If you want to understand more about how a bespoke approach to your hormone health could support your wellness journey, get in touch to book your free discovery call.