Intermittent Fasting For Women: The Benefits & Risks

Many women turn to intermittent fasting (IF) to try and solve a variety of health issues including weight loss, hormonal imbalances and to reduce insulin resistance. However, while this approach to food is about when to eat rather than what to eat, there is evidence that the results may affect women differently to men. But what is intermittent fasting, what are the benefits (and potential risks) and what does the science say about whether it is actually effective for women?

What is Intermittent Fasting?

Intermittent fasting (IF) has become increasingly popular in recent years and is an eating pattern that cycles between periods of fasting and eating. Unlike traditional diets that focus on what you eat, IF is more concerned with when you eat. However, fasting is by no means a new fad. It has been practised for millennia for a whole host of reasons including religious, ethical and to promote better health. The current most common methods include:

16/8 Method: Fasting for 16 hours and eating during an 8-hour window.
5:2 Diet: Eating normally for five days a week and reducing calorie intake to 500–600 calories on the remaining two days.
Eat-Stop-Eat: Involves fasting for 24 hours once or twice a week.
Alternate-Day Fasting: Alternating between fasting days and eating days.

How effective is intermittent fasting for weight loss?

There is scientific evidence that intermittent fasting can be effective for weight loss. Various studies and reviews have demonstrated that intermittent fasting leads to mild to moderate weight loss, typically ranging from 1% to 8% of baseline body weight. This is comparable to traditional calorie-restrictive diets.

Do you need to change your diet while intermittent fasting?

Well the idea isn’t that you binge eat or that you just stuff yourself with unhealthy fat-laden foods during the non-fasting hours. You should view intermittent fasting as a lifestyle change. So if your goal is to lose weight or to improve your health then your diet needs to reflect this too.

Decreasing your intake of carbohydrates can make a big difference for many people, or at least focusing on the ‘good’ carbs like veggies, berries, legumes, nuts and seeds. And make sure you get adequate diverse fibre to slow the release of the carbs and keep your gut microbiome happy.

Does fasting improve insulin resistance?

Intermittent fasting (IF) has also been regularly mentioned for its potential to improve insulin resistance, a condition often linked to type 2 diabetes and metabolic syndrome. Insulin resistance, a condition where the body's cells become less responsive to insulin, can lead to higher blood sugar levels. Studies have shown that IF can be effective in improving insulin sensitivity. For instance, a 2015 study published in the journal Obesity found that IF improved insulin sensitivity and reduced insulin levels in prediabetic men and women. The study indicated that these changes occurred independent of weight loss, suggesting that the timing of food intake itself plays a critical role in metabolic health.

Specifically for women, the evidence also supports the potential benefits of IF on insulin resistance, though the results can be influenced by hormonal differences and other factors unique to females. However, it is essential to note that responses to IF can vary based on individual health status, age and menstrual cycle phases.

Gut health cannot be overlooked when treating metabolic dysfunction - it can play a huge role in insulin resistance. Your gut bugs influence your levels of inflammation, your metabolism, how likely you are to crave certain foods, how you extract calories from them and how your blood sugar reacts to what you eat.

We get great feedback about how effective our low carb, Low-FODMAP, breakfast booster (although it can be eaten any time of day!) Blend11 is for both weight loss and improving insulin resistance when incorporated into an intermittent fasting schedule as it keeps you feeling fuller for longer, helps you avoid constipation AND improves your gut metabolism. It’s gluten-free, vegan-friendly, keto-friendly, diabetic-friendly, IBS-friendly … basically it can be enjoyed by most people!

How effective is intermittent fasting for helping to balance hormones?

As we’ve highlighted above, there is evidence that IF can influence insulin sensitivity, which is crucial for maintaining hormonal balance. For instance, the study published in the Obesity journal found that intermittent fasting improved insulin sensitivity and reduced insulin levels in overweight and obese women, which can help regulate hormones such as estrogen and progesterone. Improved insulin sensitivity can also mitigate the risk of polycystic ovary syndrome (PCOS), a condition characterised by hormonal imbalances and insulin resistance.

Additionally, intermittent fasting may positively affect other hormones like cortisol and leptin. A study published in the Journal of Translational Medicine showed that intermittent fasting led to a decrease in leptin levels and an increase in adiponectin, a hormone that improves insulin sensitivity. In some women, this hormonal adjustment can help manage weight and reduce inflammation, further contributing to hormonal equilibrium.

Does Intermittent Fasting Affect Women Differently To Men?

There is evidence that Intermittent Fasting can affect women differently compared to men due to differences in hormones, metabolism and overall physiology. Here are the main differences:

Hormonal Differences

Menstrual Cycle: Women's hormonal fluctuations during the menstrual cycle can impact how they respond to intermittent fasting. Some women may experience disrupted menstrual cycles or hormonal imbalances when fasting for extended periods.
Reproductive Hormones: Women have more sensitive reproductive hormones (like estrogen and progesterone) that can be affected by calorie restriction and fasting. This sensitivity can lead to changes in ovulation and fertility.

Metabolic Differences

Metabolic Rate: Women generally have a lower basal metabolic rate than men, which means their bodies use energy more slowly. This can affect how they respond to calorie restriction and fasting.
Blood Sugar Levels: Women may experience more significant drops in blood sugar levels during fasting, which can lead to symptoms like dizziness, fatigue and irritability.

Appetite and Eating Behavior

Hunger Hormones: Women may experience more pronounced fluctuations in hunger hormones, like ghrelin, during fasting. This can make intermittent fasting more challenging for some women compared to men.
Emotional Eating: Women are often more susceptible to emotional eating and may find it harder to adhere to fasting schedules due to stress or emotional triggers.

Fat Loss and Muscle Mass

Fat Storage: Women tend to store fat differently than men, often in the hips, thighs and buttocks. This distribution can affect how fat loss occurs during intermittent fasting.
Muscle Mass: Men generally have more muscle mass, which can lead to different results in body composition changes during fasting. Women may need to be more mindful of maintaining muscle mass through resistance training and adequate protein intake.

Health and Well-being

Stress Response: Women may have a more pronounced stress response to fasting, potentially leading to increased cortisol levels. This can affect overall well-being and adherence to fasting protocols.
Bone Health: Prolonged fasting or very low-calorie intake can impact bone health, particularly in women, increasing the risk of osteoporosis over time.

Practical Considerations for Women

Cycle Syncing: Some women find it beneficial to adjust their fasting schedules according to their menstrual cycle, fasting less or consuming more calories during certain phases.
Nutrient Intake: Ensuring adequate nutrient intake, especially of iron, calcium and vitamin D, is crucial for women to prevent deficiencies and maintain overall health.
Mindful Eating: Incorporating mindful eating practices and paying attention to hunger and fullness cues can help women navigate intermittent fasting more effectively.

It's essential for women to listen to their bodies and adjust fasting protocols as needed.

Other potential benefits of Intermittent Fasting

1. Cellular Repair and Longevity

Autophagy: Fasting triggers autophagy, a process where cells remove damaged components, which may contribute to longevity and disease prevention.

Reduced Inflammation: Fasting can reduce inflammation and oxidative stress, which are linked to various chronic diseases.

2. Mental Clarity and Brain Health

Brain Function: Fasting may enhance brain function and protect against neurodegenerative diseases.

BDNF Levels: Increased levels of brain-derived neurotrophic factor (BDNF) support brain health and cognitive function.

What are the potential risks of Intermittent Fasting?

1. Nutritional Deficiencies

Balanced Diet: It's crucial to consume nutrient-dense foods during eating windows to avoid deficiencies.

2. Eating Disorders

Disordered Eating: IF is not suitable for everyone. It can exacerbate unhealthy eating behaviours in individuals with a history of eating disorders.

3. Blood Sugar Control

Hypoglycemia: Those with diabetes or blood sugar issues should approach IF with caution and consult healthcare professionals.

4. Hormonal Imbalances in Women

Menstrual Cycle: Fasting can disrupt menstrual cycles and affect fertility in some women.

5. Muscle Loss

Lean Mass: Extended fasting periods without adequate protein intake can lead to muscle loss.

Conclusion

Intermittent fasting can be a powerful tool for weight management, metabolic health and potentially greater hormonal balance. However, it's not a one-size-fits-all solution. The effectiveness and safety of IF depend on individual health conditions, lifestyle and nutritional needs. Consulting with a healthcare professional before starting any fasting regimen is essential to ensure it aligns with your personal health goals and circumstances.

References

Healthline: Intermittent Fasting 101
Obesity Journal
PMC Article on Intermittent Fasting and Insulin Sensitivity
UIC Today: Research review shows intermittent fasting works for weight loss, health changes
Harvard T.H. Chan School of Public Health: Intermittent Fasting
PubMed Central: The Effects of Intermittent Fasting on Health Markers
National Institute on Aging: Fasting and its Effects on Health