Is Intermittent Fasting OK for Women?

Intermittent fasting (IF) throws out the idea of eating regular meals a day and instead adopts the practice of going without food for a prolonged period of time, whilst limiting the hours allowed to eat. It’s sold as having many health benefits with some studies claiming it prolongs life. But at what cost and is it for everyone? As a woman I want to find out what’s it doing to my hormones which are already riding the monthly rollercoaster!!

We live in a time where food is in abundance and constantly shoved in front of us, whether it be at work, while shopping, commuting, watching sport and even when refuelling the car, it’s everywhere. So the thought of fasting with so much temptation around just doesn’t seem realistic as a long term health solution.

There are many theories on how to fast, with some popular strategies including:

  • Restricted eating windowlimiting your eating window to just 8 to 12 hours a day.
  • Michael Mosely’s 5:2 fastrestricts calories to 500 calories/day for 2 days and 5 days of eating what you want.
  • Alternate-day fasting: as the name suggests you fast on one day and have a free day of eating the next day.

Due to so many different opinions on how to approach fasting we are seeing varied results in the scientific literature, and like with most dietary guidelines what works for you doesn’t mean it will work for your neighbour.

So what happens to women when they fast?

Whilst I personally have not experienced any adverse effects from IF, women have reported in my clinic a range of symptoms including of anxiety, changes in sleep, hormonal imbalances and reproductive issues.

IF studies in humans are thin on the ground, especially when looking at the effects of IF on women specifically. That said there are recent animal studies (Kumar et al, 2013) which report IF negatively influences reproduction in young rats. Nutritional infertility is very common where women fail to eat enough to match their energy expenditure. I think this highlights the importance for females of a reproductive age and of normal weight they should tread cautiously until more robust studies are carried out.

Another study by Heilbronn et al (2005), reported adverse effects on metabolic markers in non-obese women, as a result of alternate-day IF, but improved insulin sensitivity and glucose tolerance was seen in non-obese men.

By comparison obese men and women undertaking IF revealed both sexes experienced metabolic benefits; indicating positive metabolic results in women may be limited to her body weight.

For these reasons, women need to have greater awareness when embarking on such dietary changes. If you do decide to take on IF, tune into your body and ask yourself honestly - is my health suffering? If you answer yes to any of these then reassess and consider STOPPING ..

  • Have I noticed any changes to my monthly cycles?
  • Am I experiencing disrupted sleep?
  • Am I of normal body weight?
  • Is my skin developing acne?
  • Is my appetite stronger?
  • Have I lost my appetite altogether?

Dial into your own intuition and start trusting your own instincts about your body – if it doesn’t feel right, then accept that it isn’t serving you and this is NOT your fault.

Yours in health