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Intermittent Fasting for Women A Beginner's Guide

Intermittent Fasting für Frauen Ein Anfänger Ratgeber

Intermittent fasting has become an increasingly popular form of diet and nutrition in recent years. Unlike most other diets that tell you what to eat, intermittent fasting focuses on when to eat by incorporating short, regular periods of fasting into your diet.

This type of diet can help you eat fewer calories, lose weight, lower your risk of diabetes and reduce your risk of heart disease.

However, a number of studies suggest that intermittent fasting may not be as beneficial for women as it is for men. For this reason, it might make sense for women to follow a modified approach.

Here's a detailed intermittent fasting guide for women.

What is intermittent fasting?

Intermittent Fasting (IF) describes a dietary regimen that involves a cyclical alternation between periods of fasting and normal eating. The most common methods of intermittent fasting include fasting on alternate days, fasting daily for 16 hours or fasting for 24 hours two days a week. For the purpose of this article, the term intermittent fasting is used as an umbrella term for all of these variations.

Unlike most other diets, intermittent fasting does not involve controlling calorie or macronutrient intake. In fact, there are no rules about what foods should be eaten or avoided, making intermittent fasting more of a lifestyle than a diet.

Many people use intermittent fasting to lose weight as it is a simple, convenient and effective way to eat less and lose body fat (1, 2). It can also help reduce the risk of heart disease and diabetes, maintain existing muscle mass while dieting and maintain psychological well-being (2, 3. 4).

In addition, this dietary pattern can help save time in the kitchen as you will need to plan and prepare fewer meals (5).

Summary: Intermittent fasting is a dietary pattern that involves regular, short-term periods of fasting. It is a popular lifestyle choice that has potential benefits for weight loss, body composition, disease prevention and well-being.

Intermittent fasting may have different effects on men and women

There is evidence that intermittent fasting may not be as beneficial for some women as it is for men. One study showed that blood glucose control worsened in women after three weeks, which was not the case for men (6).

There are also some anecdotal reports of women experiencing changes in their menstrual cycle after starting intermittent fasting. Such shifts occur because the female body is extremely sensitive to calorie restriction.

When calorie intake is low - as can be the case with prolonged or frequent fasting - an area of the brain known as the hypothalamus is affected. This can interfere with the release of gonadotropin-releasing hormone (GnRH) - a hormone that helps release two reproductive hormones: luteinizing hormone (LH) and follicle stimulating hormone (FSH) (7, 8).

If these hormones cannot communicate with the ovaries, there is a risk of irregular periods, infertility, poor bone health and negative effects on other areas of health (7).

Although there are no comparable human studies, research conducted with rats has shown that 3 to 6 months of fasting on alternate days can cause a reduction in ovarian size and irregular reproductive cycles in female rats (9, 10).

For these reasons, women should consider a modified approach to intermittent fasting that includes shorter periods of fasting and fewer fasting days.

Summary: It may be that intermittent fasting is not as beneficial for women as it is for men. To reduce potential negative effects, women should consider a milder approach to fasting: shorter fasts and fewer fasting days.

Health benefits of intermittent fasting for women

Intermittent fasting not only has a positive effect on waist circumference, but could also reduce the risk of developing a number of diseases.

Intermittent fasting and heart health

Heart disease is the leading cause of death worldwide (11). High blood pressure, high LDL cholesterol levels and high triglyceride levels in the blood are among the leading risk factors for developing heart disease.

A study of 16 obese men and women showed that intermittent fasting reduced blood pressure by 6% in just eight weeks (2). The same study also found that intermittent fasting reduced LDL cholesterol levels by 25% and triglyceride levels by 32%.

However, the evidence for the link between intermittent fasting and improved LDL cholesterol and triglyceride levels is not consistent. A study conducted with 40 normal weight subjects during the Islamic month of Ramadan did not result in a reduction in LDL cholesterol and triglyceride levels (12).

High-quality studies with more robust methods are needed before scientists can fully understand the effects of intermittent fasting on heart health.

Intermittent fasting and diabetes

Intermittent fasting could help reduce the risk of diabetes. Similar to continuous calorie restriction, intermittent fasting also appears to reduce some risk factors for diabetes (3, 13, 14). It does this by lowering insulin levels and reducing existing insulin resistance (1, 15).

In a randomized controlled trial of more than 100 overweight or obese women, 6 months of intermittent fasting reduced insulin levels by 29% and existing insulin resistance by 19%. The blood glucose levels themselves, however, remained unchanged (16).

In addition, 8 to 12 weeks of intermittent fasting has been shown to reduce insulin levels by 20 to 31% and blood glucose levels by 3 to 6% in people suffering from prediabetes, a condition in which blood glucose levels are not yet elevated enough to diagnose diabetes (3).

However, intermittent fasting may not be as beneficial for women as it is for men when it comes to controlling blood sugar. One small study found that blood sugar control worsened in women after 22 days of fasting on alternate days, while no negative effects on blood sugar were observed in men (6).

However, despite this side effect, reducing insulin levels and existing insulin resistance would still likely reduce the risk of diabetes, especially for people who already have prediabetes.

Intermittent fasting and weight loss

Intermittent fasting can be an easy and effective way to lose weight when used correctly, as regular short-term fasting can help you consume fewer calories and lose fat.

A number of studies suggest that intermittent fasting is just as effective as traditional calorie-restricted diets when it comes to short-term weight loss (17, 18).

A 2018 study review that looked at studies conducted with overweight adults concluded that intermittent fasting led to an average weight loss of 6.8 kilograms over the course of 3 to 12 months (18).

Another study review showed that intermittent fasting reduced body weight in overweight or obese adults by 3 to 8% over the course of 3 to 24 weeks. This review also found that study participants reduced their waist circumference by 3 to 7% during the same period (3).

It should be noted that studies on the long-term effects of intermittent fasting on weight loss in women are still pending.

In the short term, intermittent fasting appears to support weight loss. However, the amount of weight lost will depend on the number of calories you consume during non-fasting periods and how long you follow this lifestyle.

Intermittent fasting could help you eat less

Changing your diet to intermittent fasting could naturally help you to eat less. One study found that young men ate 650 kcal less per day when their food intake was restricted to a 4-hour window (19).

Another study of 24 healthy men and women looked at the effects of a long, 35-hour fasting period on eating habits. Despite consuming additional calories on the days following the fast, the subjects' calorie intake fell by 1,900 kcal, a very significant reduction (20).

Other health benefits of intermittent fasting

A number of studies conducted with animals and humans suggest that intermittent fasting may have other health benefits:

  • Reduced inflammation: Some studies show that intermittent fasting can reduce key markers of inflammation. Chronic inflammation can lead to weight gain and numerous health problems (12, 21, 22).
  • Improved psychological well-being: One study concluded that eight weeks of intermittent fasting reduced depression and binge eating, while also improving body image in obese adults (4).
  • Increased longevity: Intermittent fasting has been shown to extend the lifespan of rats and mice by 33 to 83%. However, the effects on longevity in humans have not yet been sufficiently investigated (23, 24).
  • Maintaining muscle mass: Intermittent fasting appears to be better for maintaining muscle mass than continuous calorie restriction. More muscle mass helps you burn more calories even at rest (25, 26).

The health benefits for women in particular need to be studied more extensively in well-designed human trials before final conclusions can be drawn (27).

Summary: Intermittent fasting may help women lose weight and reduce their risk of diabetes and heart disease. However, further human studies are needed to confirm these results.

The best types of intermittent fasting for women

When it comes to diet and nutrition, there is no universal approach that is best for all people. This also applies to intermittent fasting. In general, women should use a more relaxed approach to fasting than men. This could include shorter fasting periods, fewer fasting days and/or consuming a small amount of calories on fasting days.

Here are some of the best types of intermittent fasting for women:

  • Crescendo method: fasting for 12 to 16 hours on two to three days per week. Fasting days should not be consecutive and should be split evenly throughout the week (e.g. Monday, Wednesday and Friday).
  • Eat-stop-eat (also known as a 24-hour protocol): A full 24-hour fasting period once or twice a week (maximum twice a week for women). Start with 14 to 16 hour fasting periods and gradually extend them.
  • The 5:2 diet (also known as "The Fast Diet"): Restrict calories to 25% of your usual calorie intake (about 500 kcal) on two days per week and eat normally on the other 5 days. There should be one day without fasting between fasting days.
  • Modified fasting on alternate days: You fast every other day and eat normally on the non-fasting days. You are allowed to consume 20 to 25% of your usual calorie intake (approx. 500 kcal) on the fasting days.
  • The 16/8 method (also known as the "Leangains method"): You fast for 16 hours a day and eat all your calories during an 8 hour window. Women should start with a 14-hour fasting period and possibly extend this to 16 hours.

Regardless of which approach you choose, it is still important that you eat well during the non-fasting periods. If you eat large amounts of unhealthy foods with high calorie density during the non-fasting phases, you will not reap the same weight loss and health benefits.

At the end of the day, the best approach is the one that works best for you and that you can stick to in the long term - and of course should not result in negative health effects.

Summary: There are several ways for women to do intermittent fasting. Some of the best methods include the 5:2 diet, modified fasting on alternate days and the crescendo method.

How to get started with intermittent fasting

Getting started with intermittent fasting is easy. In fact, we have all done many intermittent fasting phases before. Many people instinctively eat this way by skipping breakfast or dinner.

The easiest way to start intermittent fasting is to choose one of the intermittent fasting methods described above and give it a try. You don't necessarily have to follow a structured plan. An alternative is to fast whenever it suits you best. Skipping meals from time to time when you don't feel hungry or don't have time to cook can work for some people.

At the end of the day, it doesn't matter what type of fast you choose. The important thing is to find a method that works best for you and your lifestyle.

Summary: The easiest way to get started with intermittent fasting is to choose one of the above methods and give it a try. Stop this trial immediately if any unwanted side effects occur.

Safety and side effects of intermittent fasting

Modified versions of intermittent fasting appear to be the safest for women. Some studies have reported some side effects including hunger, mood swings, impaired concentration, reduced energy, headaches and bad breath on fasting days (1, 18).

There are also some reports online of women whose menstrual cycles have become unbalanced during an intermittent fasting diet, or whose periods have stopped altogether.

If you have a medical condition, you should consult your doctor before trying intermittent fasting. A medical consultation is especially important for women,

  • Who have a history of eating disorders.
  • Who suffer from diabetes or regularly have low blood sugar levels.
  • Who are undernourished or malnourished or suffer from nutritional deficiencies.
  • Who are pregnant, breastfeeding or trying to conceive.
  • Who suffer from fertility problems or have a history of amenorrhea (missed periods).

At the end of the day, intermittent fasting appears to have a good safety profile. However, you should stop immediately if you experience any problems such as a missed menstrual cycle.

Summary: Intermittent fasting can cause hunger, reduced energy levels, headaches and bad breath. Women who are pregnant, trying to become pregnant or have a history of eating disorders should seek medical advice before starting an intermittent fasting protocol.


Intermittent fasting is a nutritional approach that involves regular, short periods of fasting. The best types for women include a daily 14 to 16 hour fast, the 5:2 method or modified fasting on alternate days.

Although intermittent fasting has been shown to be beneficial for heart health, diabetes and weight loss, there is some evidence that it may have negative effects on reproduction and blood sugar levels in some women.

Nevertheless, modified versions of intermittent fasting appear to be safe and harmless for most women and may be a more maintainable option than longer and stricter fasting protocols.

If you're a woman looking to lose weight or improve your health, intermittent fasting is certainly a diet to consider.




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