Intermittent fasting has become a popular trend in the wellness industry due to its many health benefits. Though humans have been practicing fasting for thousands of years, the science is now confirming how it can be used as a therapeutic healing tool.
Intermittent fasting is basically the practice of consuming one's daily calories during a limited window of time, or going for prolonged periods of time without eating.
There are many different methods of intermittent fasting which may include daily 12 to 16-hour fasts or fasting for 24 hours once or twice per week.
Evidence now indicates that intermittent fasting has a variety of positive effects in the body including :
- Improving blood sugar regulation and heart health (1)(2)(3)
- Reducing inflammation (4)
- Preventing and treating certain cancers (5)(6)
- Promoting weight loss and increasing metabolic rate (5)
- Improving cognitive function and memory (6)
Why does intermittent fasting have so many benefits?
Being in a fasted state activates cellular pathways that initiate important cellular repair processes and improve our defense against oxidative and metabolic stress (7).
This includes the process of autophagy, where cells recycle and remove old and dysfunctional molecules that build up inside of cells (8).
Intermittent fasting can be a very powerful tool that can benefit the body and brain in numerous ways.
But what about women of reproductive age? Today we will be looking at fasting from a female perspective with some important factors to consider before deciding on whether fasting may be beneficial for you.
The effects of fasting on women's hormones
Though intermittent fasting has been associated with many health benefits, it can be a bit more complicated for women as it has been linked to hormonal disruption in particular among women of reproductive age.
The reality is that most studies to date have been conducted among men or postmenopausal women, representing a very different hormonal picture than among reproductive age women. The results of intermittent fasting have been more beneficial among men with mixed results among women.
A study found that fasting may adversely affect the glucose and insulin response among women compared to men who experienced improvements in their insulin levels (11).
Women are particularly sensitive to periods of "famine" which is why going too long without food can activate the stress response. When the body goes into "starvation mode" because it anticipates lack of food, it may hold onto weight and inhibit sex hormone production and reproductive function by invoking changes in the hypothalamus-pituitary-thyroid axis (12)(13).
This can go on to disrupt the secretion of the reproductive hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH), but also drops in estrogen and progesterone, which can throw off hormonal balance.
Food and calorie restriction is perceived as a stressor by the female body in particular, and as a result the production of sex hormones necessary for ovulation and menstruation may become compromised (14). Going too long without food can negatively impact hormonal balance but also reproductive health.
Fasting may be more beneficial for women post menopause however for women dealing with hormonal imbalances and high stress during their reproductive years, longer and more intense fasting is not recommended.
Intermittent fasting for women
Though longer fasts may cause some imbalances for cycling women, there are still ways to make intermittent fasting work in a way that is safe and even beneficial for your hormones and female physiology.
Intermittent fasting tips for women:
- Stick to 12-13 hour fasts at a time
- Avoid skipping breakfast
- Aim for a balanced breakfast within 90 minutes of waking
- Avoid fasting during your bleed
- Avoid consecutive days of fasting
- Be sure to eat enough calories and macronutrients during your feeding window
Research points towards consuming most of your calories at the beginning of your day as most beneficial therefore if you do want to adopt intermittent fasting in a way that also supports hormonal balance, a fasting window of 12 hours with an earlier dinner seems to work best. That being said, experimenting with what works best for you is always encouraged. Be sure to track and pay attention to any changes that occur and to discontinue if any symptoms get worse.
Intermittant fasting is not recommended for pregnant and breastfeeding women.
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