Fasting is one of the most ancient traditions that has been practised for thousands of years. It is the voluntary withholding of food for spiritual, health, or other reasons. In today’s Western world we have lost touch with these, but you may hear that fasting is making a comeback due to its proposed health benefits.
Specifically, if you are in the fitness world, you may have come across the term intermittent fasting (IF). IF for women can be beneficial for weight loss, but as with all things diet and health-related, people are very individual. There is not a one size fits all approach. Women especially may want to be more careful in considering fasting as a health tool.
Fasting Versus Intermittent Fasting
As you probably know fasting is defined as willingly withholding food for a determined period of time. IF is a little different and involves a more calculated approach. There are a number of different IF “protocols”; however, the most common IF for “lean gains” is a 16-hour fast/8-hour feed. Most people fast overnight, between dinner and breakfast. Some people take a whole 24 hour fast 1-2 times a week, and yet others are completely random.
Because the research is so limited, no one really knows which type of fasting is best for different goals – whether that’s fat loss, muscle preservation, disease prevention, or longevity.
Yet, fasting for 12+ hours each day has shown the potential to extend the lifespan due to cellular repair and hormonal benefits. It may also help regulate blood sugar levels, control blood lipids, maintain lean mass, and assist with weight loss. At the moment, it may be a good 5-7 years before we know what exactly IF does in humans (and why), and another 10-12 years from knowing which IF protocols are “best”.
Intermittent Fasting and Hormones
Keep in mind that women’s bodies want them to make babies and continue to populate the world. Further, women have sensitive endocrine systems that essentially prevent starvation and excessive stress so we can protect a developing fetus. If the female body senses starvation or stress, hunger hormones increase. The hunger hormones, ghrelin and leptin, tell us when to eat and when we are full. Women are more susceptible to elevated ghrelin production after fasting, which may cause binge eating in response to fasting or may exacerbate disordered eating behaviour.
Fasting or IF can also affect thyroid function and fertility in some women, especially if it’s not done properly, done too often, or the woman already has weak adrenals or a hormone imbalance.
To give you a little more background as to why this may happen. In both men and women, hypothalamic-pituitary-gonadal (HPG) axis — the cooperative functioning of three endocrine glands — acts a bit like an air traffic controller.
- First, the hypothalamus releases gonadotropin-releasing hormone (GnRH).
- This tells the pituitary to release luteinizing hormone (LH) and follicular stimulating hormone (FSH).
- LH and FSH then act on the gonads (a.k.a. testes or ovaries).
- In women, this triggers the production of estrogen and progesterone — which we need to release a mature egg (ovulation) and to support a pregnancy.
This chain reaction happens on a very specific, regular cycle in women, so GnRH pulses must be very precisely timed, or everything can get out of whack. GnRH pulses seem to be very sensitive to environmental factors and can be thrown off by fasting.
Presently there isn’t yet much research on IF and benefits for women. So here is a little advice if you are looking to try IF as a woman.
Intermittent Fasting for Women
I often steer women away from IF, but I do think it has benefits.
If you do have a history of eating disorders, you have hypoglycemia, adrenal fatigue or hypothyroidism that’s not controlled, or you’re underweight, you may want to think twice about IF. Also, women who are pregnant, want to become pregnant, or who have had trouble conceiving should steer clear of IF.
If you’re a woman who is of normal weight for your height, or you have 10 or so pounds to lose, try IF on a few non-consecutive days during the week. You don’t need to IF every day. For instance, when doing the 12-16 hour fast, you’d stop eating after dinner at 7 pm and then don’t eat anything again until 7 am the following morning. You can have water, coffee, or tea, but no kinds of milk or sweeteners in these liquids and then nothing else.
If you have more than 30 pounds to lose, try IF more often, maybe 5 days a week. You also have the option of one full 24-hour fast day a week. See what works for your body.
Is Intermittent Fasting Working?
If IF is working for you, you should notice weight loss (if that’s your goal), improved blood sugar levels (try to monitor this with a glucometer), energy boost, improved clarity, and good sleep. In essence, you should feel good.
What Are the Warning Signs?
If you’re trying IF and you notice any of the following, you may need to make adjustments:
- Menstrual cycle stops or becomes irregular
- Problems falling asleep or staying asleep
- Hair falls out
- Start to develop dry skin or acne
- Don’t recover from workouts as easily
- Injuries are slow to heal, or you get every bug going around
- Tolerance to stress decreases
- Moods start swinging
- Heart starts going pitter-patter in a weird way
- Interest in romance fizzles (and your lady parts stop appreciating it when it happens)
- Digestion slows down noticeably
- Always seem to feel cold
If you were going for a full 16 hours, try just 12. If you were doing it every day, try only 2-3 days a week. Make some adjustments and revisit.
Of course, not everyone needs to IF. I do recommend at least an 8-10 hour fast overnight to give your body a chance to build and repair itself while you are sleeping. It can’t focus on its nightly duties when you have a belly full of food to digest. That’s one reason people don’t sleep well. What I recommend first and foremost is to establish best practices in your own exercise and nutrition habits, right now. Then once you have that experience to rely upon, tweak away to your heart’s desire.
Article written by Courtney Chisholm, Registered Dietitian.