Is intermittent fasting right for you and your hormones?

16 Oct

Pre-note: My approach to my work is heavily supported by science, and I place enormous value on the research. There is some additional reading at the bottom of this post, should you want to muse over any of the studies that have informed this piece of writing.

There is some great research to back up the positive power of fasting, but like all things, when we see extreme behaviour with a diet trend, it can end up being counterproductive. Alongside the positives, research has shown links to eating disorders and compulsive behaviours. One has to also look at the whole picture with research — whom was the research carried out by, was the cohort men or women, what was the age bracket? Sadly, a lot research tends to be on younger males. I am a big fan of fasting in-between meals, as the avoidance of snacking can be great when you are looking to improve insulin sensitivity, but if you take large windows of fasting (in particular in the AM) this can be stressful for the body.

I must start by saying that I am strongly against the 5:2 — it suggests that a grown adult should aim to consume around half that of the recommended amount for a toddler — and there is a large focus on calorie content, which can overlook nutrient status and blood sugar balance. For those of you that aren’t familiar with it, the 5:2 diet consists of eating what you want five days a week, and dramatically cutting the calories for two. Following the 5:2 rules, you could eat 500 calories of ultra-processed candy for your daily intake! You then also have to deal with your strong biological desire to fuel up on food when you break a fast, which can see a yo-yo type approach to eating.

What's the science on intermittent fasting and weight loss?

There is a whole host of research that supports IF and weight loss, but if weight is the only quantified result that the study has looked into, what has gone on with muscle mass, hormonal health, electrolyte balance, and nutrient status?

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?

What are the myths around intermittent fasting that need to be debunked?

That it has to be extreme. 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.

Drinking herbal tea won’t break a fast, and a little black coffee is not likely to either, BUT sipping on coffee in a fasted state could cause havoc and overstimulate your nervous system, driving stress in the body.

Is it a one-size-fits-all approachm or should intermittent fasting be a personalised approach?

All approaches to diet and lifestyle should be personalised, and this goes for fasting too. 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.

Is there anyone who you would say intermittent fasting is definitely not suitable for?

Anyone who may have an eating disorder, or has suffered from one in the past. Anyone who is pregnant or breastfeeding.