If you search for “intermittent fasting,” you’ll most likely find a significant number of articles on the health benefits of intermittent fasting backed by positive research. But by narrowing it down to “intermittent fasting for women,” the results may come up a whole lot different.
Where is this query — “is intermittent fasting bad for women?” — coming from, to begin with?
Let’s dive deeper into what researchers have to say about it, and find out whether intermittent fasting is for you.
1. The Data on Intermittent Fasting for Women Is Limited
Ronan Oliviera, head of Health and Fitness at Mindvalley and the author of Beyond Fasting Quest, explains the idea that intermittent fasting is harmful to women comes from a misinterpretation of the scientific data of a few studies. Let’s deep dive into how they got misinterpreted:
36-hour fast study
This study was published in 2005 in the Obesity Research Journal. They had eight men and eight women fast for 36 hours and looked at their metabolic rate.
After the fast, women had a reduction in insulin response while having no significant changes in men. So the researchers concluded that intermittent fasting “may adversely affect glucose tolerance in nonobese women but not in non-obese men.”
What’s wrong with this study?
- Firstly, the study had only eight female participants, which is not representative enough.
- Secondly, fasting for 36 hours is very different from fasting for 16 hours.
Ronan affirms, “it’s expected that your blood sugar levels drop when you don’t eat for an extended period and it will take some time for your body to warm up.”
So this conclusion is unreasonable.
This study has brought up the idea of infertility as an adverse effect of intermittent fasting for women. It was done on mice that were fasting every 24 hours for 3 months. The researchers concluded that an intermittent fasting dietary restriction regimen “negatively influences reproduction in young animals.”
What’s wrong with this study?
A 24-hour fast for mice is equivalent to a week-long fast for a human. Additionally, three months of a mice’s life is equivalent to ten human years.
If this study were done on women instead of mice, the women would have had to fast every other week for a week, for ten years. Would it have dramatic adverse effects on their health and well-being?
Prolonged nightly fasting
This study was done on 2,413 women with breast cancer. They fasted for over 12 hours and were followed for four years.
The researchers found out that these women improved all health biomarkers, especially their glycemic control. They concluded that “a prolonged nightly fasting interval could reduce cancer risk and improve cancer outcomes.“
Kristina Varady, a professor of nutrition at the University of Illinois in Chicago, studies intermittent fasting in relatively large human trials. She suggests men and women respond similarly to alternate-day fasting and time-restricted eating.
She affirms, “men and women have similar adherence rates, weight loss, and body composition changes with both diets. However, the data are very limited.”
2. Fasting Can Cause Missing Periods if Done Incorrectly
Can fasting cause this condition?
For example, during Ramadan, millions of Muslims abstain from food and drink daily from dawn to sunset, and people actually experience repeated cycles of fasting and refeeding.
The study investigated whether Ramadan fasting has any effects on menstrual cycles. It was performed on 80 female college students at Hamedan University of Medical Sciences where they observed Ramadan rituals — abstaining from food and drink from dawn to dusk for roughly 30 days
The researchers found that “in participants who fast more than 15 days, the menstrual period had significantly more abnormality than participants who fast less than 15 days.”
Ronan explains that amenorrhea and other menstrual abnormalities happen when women have an aggressive sustained caloric deficit equivalent to malnutrition, with or without fasting. So it’s not fasting itself that can cause this condition but an aggressive caloric restriction.
Women who have tried intermittent fasting and experienced amenorrhea either fasted for too many hours for an extended period or malnourished their bodies when they weren’t fasting.
He adds, “when you consume little calories during your eating window, it can disrupt your hormonal and reproductive systems. So when you fast, fast. When you eat, you should eat to satiation.”
3. Fasting Is a Hormetic Stressor
The best of all medicines is resting and fasting.— Benjamin Franklin
Any fasting acts as a hormetic stressor to your body that triggers an evolutionary mechanism termed hormesis. When we experience mild stress, we can easily recover from it and get stronger and more resistant to higher doses of stress.
Men and women have inherent metabolic and hormonal differences, and it’s evident that these differences determine how we respond to a stressor like intermittent fasting.
In general, the female body is more complex and susceptible to stress than the male body. So when you start your intermittent fasting practice, it causes additional stress to your body that can lead to a compound effect.
Addressing unwanted lifestyle stressors will help you make the best out of your intermittent fasting.
And remember that intermittent fasting for women is more than just a trendy way to lose weight and get in shape. It’s a lifestyle that can unlock your greatest potential by helping you achieve your most audacious health and well-being goals.
So it’s definitely good for women if done correctly.