Intermittent Fasting Harmful to Women? Here’s What You Need to Know (2023)

There is a good chance you have heard about intermittent fasting (IF), as the popular diet has created quite the buzz over the last several years. According to a recent study done by HealthReporter, 24% of Americans confirmed they tried this method of eating in 2020, making it the most prevalent diet in the US that year. (1)

And for good reason, several studies have highlighted an array of positive health effects associated with IF, from weight loss and improved metabolic health to lower blood pressure and cholesterol levels. (2) A growing number of people have described experiencing these benefits for themselves, and even celebrities like Kourtney Kardashian and former Twitter CEO Jack Dorsey are weighing in on how IF has helped improve their health. In addition to all the reported health benefits, the big draw to IF is its convenience factor. Unlike most other dietary plans, IF is less restrictive about what you eat and more focused on when you eat it. This is appealing to many people as it gives you the freedom to eat what you want without limiting your intake of certain types of foods. Without having to go through a major pantry overhaul or dropping a fortune on food, you can start IF at any time with what you have in your kitchen right now.

(Video) Intermittent Fasting For Women | What You Need to Know

But is this diet right for everyone? As is the case for most diets, the answer is no. Nutrition is highly individualized and what works for someone else may not work as well for you, or vice versa. When it comes to IF, emerging scientific evidence suggests that women may be one demographic that should proceed with caution. Data indicates that, compared to men, women may respond differently to a diet involving fasting or severe caloric restriction. Here’s what you might want to consider if you are thinking about trying out IF for yourself.

Hormonal Changes and Your Diet

While there is still limited research regarding IF, especially when considering its widespread popularity, the developing data regarding the relationship between hormones and fasting indicate some red flags for women. A 2022 study led by Krista Varady at the University of Illinois, Chicago found that women who were on an IF diet for 8 weeks experienced a 14% reduction in a hormone called DHEA.(3) This hormone is important for promoting healthy ovarian function and egg quality, something that women who are interested in getting pregnant likely want to optimize.

(Video) Why FASTING For Women is Different & How To Do It CORRECTLY For Insane Benefits | Dr. Mindy Pelz

And while this data is an important piece of the puzzle, it is also important to note that these women were implementing a so-called “warrior diet,” where research participants were allowed a mere four-hour window to consume calories. If you’re thinking that seems like a pretty short time frame to ingest a day’s worth of nutrients, you would be right. This IF technique, when compared to the commonly used 16:8 or 14:10 methods, where you have eight and ten hours to eat respectively, is severe. As Varady reported to UIC Today, there doesn’t seem to be anything significant or special about timing when it comes to the IF diet. “All it’s doing is making people eat less,” she states. “By shortening that eating window you’re just naturally cutting calories.” (4)

Another study published in Nutrients found that IF could potentially cause a drop in testosterone in both women and men, contributing to negative health effects such as decreased metabolic health, muscle mass synthesis, and libido. (3) It’s not all bad news though, while these drops in testosterone were observed throughout the course of the study, none of the subjects reported any symptoms or negative side effects, indicating that perhaps long-term vs. short-term IF matters. That said, research is limited at this point and more data is needed.

(Video) Do Women Need More Carbs on Keto & Intermittent Fasting? – Dr. Berg

Insulin and Blood Sugar Fluctuations

An increase in insulin sensitivity and improved blood sugar levels are often touted as one health benefit spurred by IF. However, this may not always be the case. One recent study found that insulin sensitivity was actually adversely affected when female subjects engaged in IF. It is still unclear as to why this may be but is something to be cautious of, nonetheless. Again, the research is somewhat murky at this point and more long-term data is needed. (5)

Major blood sugar fluctuations throughout the day can also accompany severely restrictive IF diets. Without regular meals, your blood sugar tends to dip drastically during a fasting period before spiking during and directly after your meals. This constant up and down, rather than a steady flow of glucose availability and thus energy, can cause reduced energy stores in your body. This often leads to increased hunger and fatigue throughout the day. (2)

(Video) Intermittent Fasting For Women: Is It Safe?

The Fine Line Between Fasting and Depriving Your Body of Nutrients

The most important takeaway from the current IF data and research thus far is that we still don’t know much. This means that if you are going to try IF, knowing your body and how to fast safely is of the utmost importance. Starting with a more manageable fasting schedule like 16:8 or 14:10 (as mentioned above) is more feasible. With a more lenient IF plan, you will generally be getting enough calories and nutrients to sustain your energy needs and physiological functions throughout the day. IF schedules like the “warrior diet” or 5:2, where you eat normally for 5 days of the week and fast for two full days, can be difficult to manage at best. At worst, you could be wreaking havoc on your body and your hormone levels.

Some women should not consider IF as a viable diet option, as the cost far outweighs any potential benefits. If you know you have a history of an eating disorder or disordered eating, have preexisting health conditions (i.e., thyroid, adrenal, or autoimmune diseases), or are pregnant or trying to get pregnant, your best bet is to focus on eating nutritious, whole foods and not worry about fasting.

(Video) Is Intermittent Fasting Safe for Women?

Science has yet to settle on a definitive answer concerning the long-term effects of intermittent fasting for women. Those who practice it describe various positive results, but those results remain anecdotal until they are backed up in clinical studies. If you care about your diet and want to make sure that you're doing everything you can to give yourself the best chance at a healthy life, then you might want to think twice before choosing to follow an intermittent fasting regimen. As with all diet plans, it’s a good idea to talk to your doctor or a dietician about any drastic changes you intend to make before you jump in feet first.

1. 34 intermittent fasting statistics and facts, HealthReporter, 2022. 34 Intermittent Fasting Statistics and Facts | HealthReporter Accessed 23 February 2023.
2. Food for thought—September, DrexelNews, 2022. Food for Thought: Intermittent Fasting: Pros, Cons and Why It’s Not for Everyone ( Accessed 23 February 2023.
3. Effects of intermittent fasting on reproductive hormone levels in females and males: A review of human trials, Nutrients, 2022. Effect of Intermittent Fasting on Reproductive Hormone Levels in Females and Males: A Review of Human Trials - PMC ( Accessed 27 February 2023.
4. New data on how intermittent fasting affects female hormones, UIC Today, 2022. New data on how intermittent fasting affects female hormones | UIC Today Accessed 14 February 2023.
5. Glucose tolerance and skeletal muscle gene expression in response to alternate day fasting, Obesity Society, 2012. Glucose Tolerance and Skeletal Muscle Gene Expression in Response to Alternate Day Fasting - Heilbronn - 2005 - Obesity Research - Wiley Online Library Accessed 27 February 2023.

(Video) Is Intermittent Fasting DANGEROUS for Women?! (The SHOCKING Effect on Hormones & Fertility)

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Intermittent Fasting Harmful to Women? Here’s What You Need to Know? ›

Research with women as participants is limited, but some studies that involve rodents suggest intermittent fasting may cause changes in estrogen levels and negatively affect reproductive functions, such as menstrual regularity, fertility, pregnancy, and lactation.

Is intermittent fasting bad for women's health? ›

Is intermittent fasting safe for women? Intermittent fasting is safe for most women, although you may want to take a different approach to it than a man might. However, if you are pregnant, breastfeeding or trying to conceive, you should avoid intermittent fasting as well as any other kind of restrictive diet.

Is there anything negative about intermittent fasting? ›

Intermittent fasting may make you feel sick. Depending on the length of the fasting period, people may experience headaches, lethargy, crankiness, and constipation.

Does intermittent fasting work for all women? ›

The Research on Intermittent Fasting for Women

Overall, research shows that intermittent fasting appears to be safe and effective for most women, especially overweight and obese women, those with issues regulating blood sugar levels and blood pressure, and menopausal and post-menopausal women [18].

Why is 16 hours the magic number for fasting? ›

Insulin sensitivity helps in fat loss and protects the body from diseases such as diabetes, high blood pressure, and heart diseases. During the 16-hour fast, your body undergoes a process known as autophagy, a process where the body destroys old or damaged cells in the body.

Does intermittent fasting mess with women's hormones? ›

Studies have suggested that intermittent fasting may reduce levels of reproductive hormones in females, leading to potential problems with fertility.

Does fasting mess with women's hormones? ›

With prolonged stress (including fasting), the hypothalamus will "turn down" the production of reproductive hormones that are important for ovulation and a healthy menstrual cycle. So it's possible for fasting to be "too much" of a stressor in some women, stressing them enough to prevent healthy ovulation.

Why don t doctors recommend intermittent fasting? ›

Intermittent fasting is safe for many people, but it's not for everyone. Skipping meals may not be the best way to manage your weight if you're pregnant or breast-feeding. If you have kidney stones, gastroesophageal reflux, diabetes or other medical problems, talk with your doctor before starting intermittent fasting.

Is fasting hard on your heart? ›

One word of caution, though: Fasting can lead to an electrolyte imbalance. This can make the heart unstable and prone to arrhythmias. “So whenever we prescribe certain diets, including a very low calorie diet and protein-sparing modified fast diet, these require medical supervision.

How long does it take for 16 8 intermittent fasting to work? ›

How Long Does It Take For Intermittent Fasting To Work? After beginning your intermittent fasting routine, you could see changes in your body in as little as ten days. More significant weight loss is seen after two to ten weeks.

When should women not intermittent fast? ›

Women who should avoid intermittent fasting

Pregnancy or breastfeeding: Intermittent fasting is generally not recommended for women who are pregnant, as it may impact the growth of the baby and cause other negative side effects. Diabetes: Fasting may increase the risk of low blood sugar (hypoglycemia).

Is it OK to intermittent fast everyday? ›

Longer periods without food, such as 24-, 36-, 48- and 72-hour fasting periods, are not necessarily better for you, and may be dangerous. Going too long without eating might actually encourage your body to start storing more fat in response to starvation.

Does intermittent fasting work for belly fat? ›

Intermittent fasting is a convenient way to lose weight without counting calories. Many studies show that it can help you lose weight and belly fat.

Does lemon water break a fast? ›

The truth about lemon water and intermittent fasting

Long story short - the answer to the question “Does lemon water break a fast?” is no, lemon water does not break a fast. Lemon water contains almost no calories and zero sugars, it doesn't raise insulin levels, which means it will not break your fast (1).

Does coffee break your fast? ›

The bottom line. You can drink moderate amounts of black coffee during fasting periods, as it contains very few calories and is unlikely to break your fast. In fact, coffee may enhance the benefits of intermittent fasting, which include reduced inflammation and improved brain function.

Why am I not losing weight on 16 8 fasting? ›

When you fast for shorter durations, your body doesn't have enough time to go into ketosis. This means it won't burn stored fat, and there won't be significant weight loss. As one study concluded, a fasting window of 18-19 hours is more effective in terms of weight loss than those between 12-17 hours [11].

How do I get rid of my hormonal belly during intermittent fasting? ›

Common examples of Time Restricted Eating include fasting for 16 hours and eating for 8 hours (16:8) or fasting for 12 hours and eating for 12 hours (12:12). If you're looking to lose belly fat with Intermittent Fasting, the TRE method has been shown to be more effective.

Does fasting raise or lower estrogen? ›

A new study led by Krista Varady, professor of nutrition, found that intermittent fasting did not change the levels of certain kinds of female reproductive hormones and caused a decrease within normal ranges for another hormone.

What happens to estrogen during fasting? ›

This effect was more likely to occur when food consumption was confined to earlier in the day (eating all food before 4 pm). In contrast, fasting did not have any effect on estrogen, gonadotropins, or prolactin levels in women.

Which fasting is best for hormonal imbalance? ›

Two ways for women to reap the benefits of intermittent fasting without the side effects of hormone imbalance include the 5:2 fasting method, and the 12, 14, or 16-hour fast.

What hormone is highest during fasting? ›

Fasting is a great stimulus to HGH secretion. During fasting, there is the spike in the early morning, but there is regular secretion throughout the day as well. Hartman et al also showed a 5 fold increase in HGH in response to a 2 day fast. This HGH likely helps in the maintenance of lean mass – both muscle and bone.

Does intermittent fasting cause thyroid problems? ›

For some, intermittent fasting may lead to new or trigger previous disordered eating behaviors. Remember that the more dietary pressure you put on yourself, the more likely you are to experience inflammation. This inflammation can worsen your autoimmune reactions or interfere with your thyroid function.

Why fasting is not healthy? ›

For some, fasting may cause problems. For example, studies have found that people who regularly fast more than 16 or 18 hours a day have a higher risk of gallstones. They're also more likely to need surgery to remove the gallbladder.

What mistakes should be avoided during intermittent fasting? ›

The five common mistakes people make when intermittent fasting
  • Overindulging. While you don't need to calorie count on your non-fasting days, don't derail your efforts by reaching for the take-out and chips. ...
  • Not eating enough. ...
  • Not drinking enough water. ...
  • Pushing yourself too hard. ...
  • Overthinking it.

Does 12 hours count as intermittent fasting? ›

Twelve-hour fasting is a form of intermittent fasting (IF) also known as 12:12 that many people try for weight loss and health benefits, including improved digestion, increased energy, and improved sleep.

Is fasting good for inflammation? ›

Researchers say intermittent fasting can reduce inflammation in the body. Inflammation is one way the body fights infection, but if there is too much inflammation that can lead to various diseases.

Why does LDL go up when fasting? ›

Intermittent fasting affects cholesterol levels due to the change in metabolism from glucose to ketones. When this occurs, the body begins using lipids rather than storing them. Lipids move out of the cells, travel in the bloodstream, and go into the liver to be made into ketones.

Does fasting raise blood pressure? ›

Skipping meals, such as intermittent fasting, can lower blood pressure. The effect appears to be temporary, with blood pressure returning to its usual levels after fasting. 8 Low blood pressure while fasting also appears to be independent of dehydration, which can lower blood pressure.

Can I fast from 7pm to 11am? ›

One of the most common, easy-to-follow schedules is 16:8. This means you fast for a 16-hour period of time and eat your daily meals during an 8-hour period of time. For example, you may want to fast from 7 p.m. until 11 a.m. the next day.

How much weight can be lost if one does 16 8 intermittent fasting in a month? ›

You should aim to lose about 1% of your body weight a week. The amount of weight lost each week will slowly decrease. At 250 lbs you can expect to lose 2.5 – 3 lbs a week. But once you pass the 200-pound mark, the rate will go down to 1.5 – 2 lbs a week.

What is the best hours to do the 16 8 fasting? ›

The eating window can occur at any point in the day, but many people choose to eat between around 12 p.m. and 8 p.m. 16:8 Intermittent Fasting is most often used forFat Loss. The Examine Database covers Weight Loss & Maintenance,Obesity, and 8 other conditions and goals.

What is the first rule of intermittent fasting? ›

Eating during a 12-hour window every day (between 7 a.m. and 7 p.m., for example) and fasting for the other 12 hours. Eating during an 8-hour window every day (between 11 a.m. and 7 p.m., for example) and fasting for the other 16 hours.

What is the best intermittent fasting for a 60 year old woman? ›

Best method of intermittent fasting for older women. Although there are different methods of intermittent fasting one can follow, senior women should first consider the 16/8 method. Fasting for 16 hours with an 8-hour eating window to consume all their calories fits into most senior women's lifestyles.

How many months for intermittent fasting is good? ›

As it stands now, the current evidence supports intermittent fasting as a weight loss method for up to 12 months. Some people are also probably not right for intermittent fasting. It's not recommended for anyone who is pregnant, has diabetes or is under 18.

Is it OK to fast 16 hours everyday? ›

Though 16/8 intermittent fasting is generally considered safe for healthy adults, you should talk with your doctor if you have any underlying health conditions. This is key if you're taking any medications or have diabetes, low blood pressure, or a history of disordered eating.

Does intermittent fasting slow metabolism? ›

Metabolic switching through intermittent fasting results in improved metabolism, increased health span, and increased longevity through multiple processes [16,30].

What are the side effects of 16 8 fasting? ›

  • Hunger and cravings. It may be no surprise that hunger is one of the most common side effects related to intermittent fasting. ...
  • Headaches and lightheadedness. ...
  • Digestive issues. ...
  • Irritability and other mood changes. ...
  • Fatigue and low energy. ...
  • Bad breath. ...
  • Sleep disturbances. ...
  • Dehydration.
Apr 23, 2021

How to lose 20 pounds in a month? ›

Here are the 10 best ways to quickly and safely drop 20 pounds.
  1. Count calories. ...
  2. Drink more water. ...
  3. Increase your protein intake. ...
  4. Reduce your refined carb consumption. ...
  5. Start lifting weights. ...
  6. Eat more fiber. ...
  7. Follow a sleep schedule. ...
  8. Set reasonable goals and stay accountable.
Oct 19, 2022

Which intermittent fasting burns the most fat? ›

Alternate-Day Fasting

This is a popular approach for weight loss. In fact, research found that, in overweight adults, alternate-day fasting significantly reduced body mass index, weight, fat mass, and total cholesterol.

Does sleeping count as fasting? ›

Does sleeping count as fasting? A. Yes, while following intermittent fasting, sleeping is considered a fasting period. Therefore, one does not consume food or drinks during this state.

Does apple cider vinegar break your fast? ›

Apple cider vinegar contains only trace amounts of carbs and is therefore unlikely to negatively affect your fast. Furthermore, it may help you feel more full and maintain your blood sugar levels.

What to do if you get hungry while fasting? ›

How to Curb Hunger When Fasting (Top 10 Tips)
  1. Eat Protein-Rich, High-Fat Food While Not Fasting.
  2. Utilize Exogenous Ketones.
  3. Increase Your Electrolyte Intake.
  4. Consume Acacia Fiber.
  5. Expose Yourself to Mild Stressors.
  6. Distract Yourself.
  7. Schedule Your Fasting Hours Overnight.
  8. Drink Sparkling Water.
Jan 9, 2023

Is it OK to take probiotics while fasting? ›

4) Taking supplements is allowed and even recommended when you fast. In order to provide your body with the adequate nutrients, vitamins, minerals, and antioxidants it needs, taking supplements and even probiotics is ideal when you fast. This ensures you don't miss out on the essentials even while you're not eating.

What is a dirty fast? ›

Dirty fasting is a term used to describe consuming some calories during a fasting window. This differs from traditional fasting or “clean” fasting, which restricts all foods and calorie-containing beverages. People who practice dirty fasting will typically consume up to 100 calories during their fasting window.

What creamer is good for intermittent fasting? ›

  • Elm & Rye Mushroom Creamer.
  • Laird Superfood Non-Dairy Superfood Creamer.
  • Smart for Life Zero Calorie Coffee Creamer.
  • nutpods French Vanilla Creamer.
  • RAPID FIRE Ketogenic Creamer.
  • Bulletproof French Vanilla Creamer.
  • Coconut Cloud: Dairy-Free Coffee Creamer.
  • RAPID FIRE Protein Creamer.
Feb 9, 2023

Why I am not losing weight after 2 weeks of intermittent fasting? ›

You're eating too much during your eating window.

“If you end up consuming the same number of calories (or more) during your eating windows as before you started intermittent fasting, then you won't lose weight.”

Can I lose 10 pounds in 2 weeks intermittent fasting? ›

If your goal is to lose 10 pounds, you need a 35,000-calorie deficit. That's a big number. If you wanted to lose 10 pounds in two weeks, you'd need to cut or burn 2,500 calories per day for those 14 days. This is not realistic or healthy for anyone.

How long should females intermittent fast? ›

That means eating regular, healthy foods during a 6- to 8-hour window each day, then fasting for the remaining 16 to 18 hours. This is found to be the most sustainable method. You can use other variations of timing to get started. These include a 12/12, which is eating for 12 hours, then fasting for 12 hours.

Does intermittent fasting affect female fertility? ›

In women, intermittent fasting can negatively affect estrogen levels and other reproductive hormones, leading to menstrual irregularities and fertility issues. According to studies, the way organisms respond to food shortages can lead to a negative outcome when it comes to the quality of eggs and sperm.

What intermittent fasting is best for hormonal belly? ›

Common examples of Time Restricted Eating include fasting for 16 hours and eating for 8 hours (16:8) or fasting for 12 hours and eating for 12 hours (12:12). If you're looking to lose belly fat with Intermittent Fasting, the TRE method has been shown to be more effective.

Does intermittent fasting affect menstrual cycle? ›

Intermittent fasting may also affect a woman's menstrual cycle, as the female reproductive system is sensitive to calorie restriction. That's because fasting for long periods can affect the hypothalamus or the part of the brain that regulates hormones like estrogen that are crucial to menstruation.

Does coffee break a fast? ›

The bottom line. You can drink moderate amounts of black coffee during fasting periods, as it contains very few calories and is unlikely to break your fast. In fact, coffee may enhance the benefits of intermittent fasting, which include reduced inflammation and improved brain function.

What is the proper way to intermittent fast? ›

Eat a normal diet five days a week and fast two days per week. Eat normally but only within an eight-hour window each day. For example, skip breakfast, but eat lunch around 11 a.m. and dinner by 7 p.m.

How does 16 8 intermittent fasting work? ›

16:8 intermittent fasting is a form of time-restricted fasting. It involves consuming foods during an 8-hour window and avoiding food, or fasting, for the remaining 16 hours each day. Some people believe that this method works by supporting the body's circadian rhythm, which is its internal clock.

How do I get rid of my saggy mom belly? ›

Do's: How To Get Rid of Mommy Tummy
  1. Relax. Take time to relax to lower your body's levels of cortisol, a significant trigger for abdominal fat accumulation.
  2. Walk. Contract your tummy muscles while walking to increase abdominal strength. ...
  3. Wrap. ...
  4. Sit or stand tall.
Oct 21, 2021

How do I get rid of my apron belly? ›

4 Tips for Getting Rid of Your Apron Belly
  1. Exercise Regularly: One of the most effective ways to reduce an apron belly is to exercise regularly. ...
  2. Focus on Your Core: Besides overall exercise, focusing on your core muscles is essential. ...
  3. Eat a Healthy Diet: Your diet can also play a role in reducing an apron belly.

Does intermittent fasting affect estrogen? ›

Estrogen. Weight loss methods, including intermittent fasting, can decrease estrogen in women who are overweight or obese. These women tend to have higher estrogen levels than women who are not overweight. Higher estrogen levels can be related to increased adipose or fat tissue.

When should you stop intermittent fasting? ›

Final thoughts on stopping intermittent fasting

Extreme hunger, excessive weight loss, dehydration, low blood pressure, and weakness can be adverse health effects of fasting. If fasting is impacting your emotions, decreasing your energy levels, or causing extreme hunger, it may be time to stop.

What does the Bible say about fasting and menstruation? ›

In the third book of the Pentateuch or Torah and particularly in the Code of legal purity (or Provisions for clean and unclean) of the Mosaic Law (Leviticus 11:1-15:33), it is stated that a woman undergoing menstruation is perceived as unclean for seven days and whoever touches her shall be unclean until evening (see ...

Why you shouldn't fast on your period? ›

Fasting may cause hormonal interference, exacerbating already occurring problems. Fast lengths of 12-16 hours are usually beneficial during the entire menstrual cycle, but prolonged fasts should be avoided during your period.


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