As May marks Women’s Health Month, Lumen recognizes that knowledge is power when it comes to women's health. With the research we have today, the nutrition paradigm is shifting from the concept of calories in, and calories out; to the quality of food you should eat, and, importantly, when you should eat.
In recent years, intermittent fasting has emerged as a trending and widely searched diet due to its success in aiding weight loss and other health benefits. Many experts in the scientific community would agree and have pointed to the benefits of the fast (1).
However, whether you're a newbie or a seasoned faster, women have distinctive hormonal and metabolic variations that might pose unique health challenges when trying to lose weight. And despite their best efforts, traditional dieting and exercise might not be enough for them to reach their goals.
Following evidence-based strategies and learning from this women's guide to intermittent fasting, you'll have more insights into finding the optimal intermittent fasting schedule that works for your biology.
Let's dive in
Intermittent fasting is the process of alternating eating and fasting for a certain period of time. There are different intermittent fasting methods, including calorie restriction and fasting-mimicking diets (2).
Intermittent fasting has gained more traction in the health community because of its numerous health benefits for your body and metabolism.
Studies have shown that when we fast, we can improve insulin sensitivity, reduce inflammation, and aid in weight loss. Intermittent fasting is also a more flexible and sustainable approach to weight loss compared to other diets and is an effective tool for women looking to improve their overall health and well-being.
Intermittent fasting is a great strategy, if the timing is personalized to your unique physiology. "Everyone's metabolism is unique", says Mia Dige, Metabolic Coach and Personal Trainer, "and its ability to switch between utilizing glucose and fatty acids as energy sources might differ."
When you’re in a fasting state, your body shifts from using glucose as the primary source of energy to using stored fat, generating the metabolic switch from carb burn to fat burn. When you're fasting, your body still requires energy, but since there is a window of no food, your body turns to the calories it needs from your storage systems - glycogen and body fat.
Let’s look at the various stages of how the body responds to fasting. In the early phases, blood sugar levels drop, lowering insulin and leptin levels, while increasing glucagon and growth hormone.
These changes stimulate glycogen breakdown to produce energy and maintain your blood sugar levels in healthy ranges (4).
However, during a prolonged fasting period, the body releases stress hormones, such as cortisol, in response to the perceived lack of energy intake. These stress hormones can push the body into a state of carbohydrate metabolism, where it prioritizes burning carbohydrates over fats for energy.
This shift towards carbohydrate metabolism is due to the body's attempt to preserve its fat stores if the fasting period continues for an extended time.
Cortisol, the primary stress hormone, increases glucose production by stimulating gluconeogenesis, a process where the liver then creates glucose from non-carbohydrate sources, such as amino acids from muscle protein breakdown.
This increased glucose production can lead to the body relying more on carbohydrates for energy and less on fat stores, which may counteract the potential benefits of fasting.
Several factors affect the transition of the body’s fuel source while fasting, including your:
Remember: Before you begin fasting, it’s best to consult a healthcare professional or nutrition expert to help you determine what fasting approach is optimal for your specific needs.
Intermittent fasting is beneficial to women’s health - it helps balance several hormones that are essential to weight loss. The three most widely used intermittent fasting regimens are the time-restricted (16/8 method), the 5:2 method (fasting two days a week and eating the other five), and the alternate-day fasting (you eat one day and fast the next) (3).
Let’s take a closer at each of these and their benefits and disadvantages.
The time-restricted (16/8) method consists of fasting for 16 hours of the day and eating within an 8-hour window. It is the simplest to do, and the most flexible and appropriate for women of all ages.
This method promotes weight loss, improves glucose levels, and reduces inflammation. However, it may be difficult to stick to because it can increase hunger and cravings during the fasting period.
The 5:2 diet consists of eating normally for five days and then reducing calorie intake for the other two days. While this approach may help with weight loss and insulin sensitivity, it requires you to have discipline and develop a weekly meal plan. Additionally, it may cause hunger and irritability on fasting days.
The alternate-day fasting consists of fasting every other day. Multiple studies (5) conducted by Patterson et.al, found that alternate-day fasting resulted in weight loss as well as reductions in glucose and insulin concentrations.
On the other hand, the challenge with this approach is that you may lack consistency which could result in miscalculating fasting days, and hunger and irritability may also occur. Tracking your fasts with biofeedback would help you keep on track.
Regardless of which fast you choose, select the one that will be the most beneficial for your health goals, and remember that there is no one-size-fits-all solution.
Part of setting up an intermittent fasting plan is based on whether you are monthly cycling, in perimenopause, or menopause, says Cynthia Thurlow, NP, and author of Intermittent Fasting Transformation. She adds, "your metabolism speeds up and slows down predictably across the month - because of this, it's important to change what you eat, do intermittent fasting, and increase the intensity of your workouts each week. All of these actions optimize your metabolism."
If you have a 28-day cycle, the first 3 weeks of your cycle are the best times to fast. Your hormones are more stable, it's a great time to decrease insulin, reduce inflammation, and activate autophagy (your body's process of reusing old and damaged cell parts).
According to Cynthia, fasting during the five to seven days preceding your menstrual cycle may unknowingly lead to the depletion of nutrients and hormones necessary in the luteal phase.
If you're experiencing perimenopause, it's important to integrate fasting into a balanced lifestyle. This means getting good-quality sleep of 7-9 hours, managing your stress levels, and eating nutrient-dense meals.
If you're menopause and beyond, you can pursue intermittent fasting with few restrictions and time constraints. Cynthia adds, 'intermittent fasting can help slow down the aging process, because it regenerates your entire system, starting with your cells and mitochondria. It also helps reduce hot flashes and other uncomfortable symptoms'.
Intermittent fasting can be challenging, but it’s simple - and you've probably instinctively done it before when you skip breakfast or dinner.
For beginners, it's best to start gradually. Selecting the fasting method that best suits your health needs is also important. This can be made easier by using intermittent fasting insights suited for your metabolism.
Next, make a plan. Create a grocery list, you can use this one as a guide, with the items you will need for the week, and develop a meal plan to ensure you stay on track.
During your eating window, select foods to support your hormones, feed your microbiome and encourage metabolic flexibility. You can do this by focusing on eating essential nutrients focus on eating high-quality protein, carbohydrates, and fats to help you stay full and energized throughout the day.
Our Lumen metabolic coaches recommend:
There is not a one-size-fits-all recommended intermittent fasting schedule for weight loss, but rather it should be tailored to the individual. To find the best schedule for you, consider your health status (those with type 2 diabetes should avoid long fasting periods such as 24-hour fasts), your current work schedule, and your appetite throughout the day. Measuring your metabolism will give you a clearer idea of how your body is responding so you can optimize your fast for the best results.
To help you succeed with intermittent fasting, including how to ease into it, stay motivated, and track your progress, our metabolic coaches recommend:
Start Slowly
Stay Hydrated
Eat Nutrient-Dense Foods:
Track Your Progress:
Incorporate Active:
By utilizing real-time biofeedback, you can effectively evaluate whether you are overfasting and potentially hindering your progress toward your health goals. These insights can help prevent your fasting from working against you.
The optimal fasting duration varies for each individual, and no one-size-fits-all solution exists. Tailoring your intermittent fasting plans to suit an individual's unique requirements is essential to maximize benefits and reduce potential risks.
Is intermittent fasting healthy for women?
Under what circumstances should women not fast?
What are the effects of over-fasting for women?
Can I exercise while fasting?
Can I drink coffee or tea during my fasting window?
Can I combine intermitted fasting with carb cycling?
Although intermittent fasting can be challenging, it can offer many health benefits, including weight loss, improved insulin and glucose levels, and reduced inflammation, as well as potential improvements for those with hormonal issues.
By restricting certain foods on specific days, you can build discipline and establish a long-term, sustainable way of living a healthier and well-balanced life. If you are looking to lose weight or improve your health, intermittent fasting is something to consider.
Everyone has different physiological needs, health conditions, and lifestyle factors that can affect your intermittent fasting regimens. It is important to consider your individual needs to maximize the benefits while minimizing potential risks. Remember to be kind to yourself as you begin to change your lifestyle and health goals.
If you're pregnant or breastfeeding, underweight, or suffering from a preexisting condition or chronic stress or eating disorder, consult a professional physician before starting any type of fast.
Marine is a registered dietitian with a passion for well-being, health and metabolism. She started her career as a clinical dietitian, opened her private practice to accompany patients from various backgrounds in their health journey, and is now providing nutrition support for Lumen’s customers.