Should you Follow Intermittent Fasting for PCOS?


What is Intermittent Fasting?


Intermittent Fasting (IF) has become increasing popular in recent years. Fasting is a method used by religious groups, for traditional or cultural reasons, but has now become the new dieting craze. Intermittent Fasting, however, is not a diet, it is a method used to schedule eating times. But it has a whole host of health benefits.


Due to IF popularity different types/methods have been developed, all of which are effective. However, which one works well for you is dependent upon the individual.


Types of Intermittent Fasting


The 16/8 Method


The 16/8 method involves fasting for a maximum of 16 hours every day with an "eating window" of 8 hours. You can decide when your 16 hour fast begins, this method can be as simple skipping breakfast or not eating anything after dinner. The "eating window" is the time period you have to consume all of your calories.


For example, if you consume your last meal at 11 pm and do not eat anything until 3 pm the next day, you have fasted for 16 hours between your meals.


Drinking water, coffee or any other non- caloric beverage is allowed during the fasting window and this can help suppress your appetite and hunger cues.


The 5:2 Fasting Diet


The 5:2 diet involves eating normally for fives day and then restricting your calories by 500-600 for 2 days out of the week. It is recommended that women reduce their calories by 500.

Fasting days can be taken any day you like, as long as you are not fasting 2 days consecutively.




Eat-Stop-Eat includes a 24 hour fast once or twice a week. There different ways to approach a 24 hour fast, for example, if you eat your last meal on Saturday 3rd March at 6 pm and then eat again on Sunday 4th March at 6 pm, you have done a 24 hour fast.


You can approach a 24 hour fast in whatever way you want, lunch one day to lunch the next day or dinner one day to dinner the next day, as long as it is a 24 hour fast.


The Warrior Diet


This method of fasting follows a daily cycle of undereating and overeating. The premise of the Warrior Diet is that for 10 to 18 hours a day you eat light snacks of raw fruits or vegetables or a light protein food like yogurt, as well as exercising during the undereating period and then at night you eat one large meal.


Alternate-Day Fasting


Alternate-Day fasting involves fasting every other day. There are different versions of this type of fasting. Some of them allow only 500 calories during fasting days and allow you to eat whatever you like on non - fasting days.


Spontaneous Meal Skipping


This is something we all may do intentionally but also unintentionally. Often we may wake up in the morning and we are not hungry, therefore we might skip breakfast. It is a myth that people need to eat every 3 hours or their body will go into "starvation mode" and they will become catabolic.


For many people, intermittent fasting may sound bonkers, however, as Dr. Mattson said, “From an evolutionary perspective, it’s pretty clear that our ancestors did not eat three meals a day plus snacks”. Our ancestors did not have fridges or food cupboards to store food. Our bodies are able to survive long periods of time without food and give our body a break from digestion may actually be beneficial.


Now that we have discussed the different methods/types of intermittent fasting, let's take a look at why Intermittent Fasting has become a popular therapeutic tool in the treatment of PCOS.


Benefits of Intermitted Fasting for PCOS


Reduces insulin levels


Fasting lowers insulin levels, initiating fat burning. Research undertaken by Mattson indicates "if you don’t eat for 10–16 hours, your body will go to its fat stores for energy, and fatty acids called ketones will be released into the bloodstream".


However, several studies suggest intermittent fasting has no clear effect on glucose homeostasis and no effect on insulin levels. Studies have also found consuming only one unusually large meal per day worsens morning glucose tolerance compared to a diet which spread calories across three meals.


Furthermore, it is important to keep in mind that studies show fasting for women can effect blood sugar levels.


Facilitates Weight Loss


Sadiya et al conducted a 4-week study and found fasting reduced total body weight, body mass index, and waist circumference. It is suggested that decrease in waist circumference correlates to improved insulin sensitivity.


The Alternate Day Fasting (ADF) method was used for a 12-week study by Vardy et al. The study showed how alternate day fasting was an effective tool for weight loss. Participants in the ADF group body weight decreased (P < 0.001) by 5.2 ± 0.9 kg (6.5 ± 1.0%) relative to the control group, by week 12. Furthermore, fat mass was reduced (P < 0.001) by 3.6 ± 0.7 kg.


Reproductive Health


Research has identified fasting can help correct ovulatory consequences, due to the increase luteinizing hormone, as a result of short-term calorie restriction, in obese women with PCOS.


Regeneration of entire immune system


Research suggests that fasting allows regeneration to occur. Fasting sends a message prompting stem cells to produce new white blood cells, regenerating the entire immune system. Essentially the body is able to remove old or damaged parts during the fasting period.


Research also found prolonged fasting also reduced the enzyme PKA, which is linked to ageing and a hormone which increases cancer risk and tumour growth.


Depression and Anxiety


Women with PCOS have higher rates of depression and anxiety.  Research has shown that fasting can help reduce symptoms of anxiety and depression and improve social functioning. Fasting has also shown to increase vigilance and improve mood.


Mark Mattson's studies show intermittent fasting- limiting caloric intake at least two days a week- can help improve brain health. It is suggested fasting a few days a week might help protect your brain from neurodegenerative diseases like Alzheimer’s and Parkinson’s.


Reduces Stress Levels


Stress is a likely cause of PCOS and it is something we have to learn to manage in order to not only manage our PCOS but also heal our body. Studies have identified that IF helps decrease stress levels. Alternate Day Fasting has shown to reduce oxidative stress and inflammation. Oxidative stress is defined as a disturbance in the balance between the production of reactive oxygen species (free radicals) and antioxidant defenses.


Research suggests women with PCOS suffer from chronic sympathetic overactivity, this may be due to the prevalence of insulin resistance, central obesity and obstructive sleep apnea. An overactive sympathetic nervous system can cause the adrenals to release cortisol instead of adrenaline. An overproduction of cortisol over time can lead to chronic illnesses. IF can help reduce the chronic sympathetic overactivity in PCOS and this will, in turn, reduce stress neurohormone levels.


Improves Cardiovascular Risk


In Vardy et al's study, results identified significant benefits of IF for cardiovascular health. Results showed a reduction in blood pressure and heart rate. As well as improvements in lipid profile, with a decrease in total cholesterol and LDL-cholesterol levels and an increase in HDL-cholesterol levels.


Should you follow Intermittent Fasting?


There is no clear answer. Yes, there are benefits to IF, however, studies have not found any concrete benefits to fasting for insulin resistance. Research suggests that it is not the fasting alone that brings about health benefits, it is a reduction in calories. A reduction in total calories will lead to weight loss and in turn improve insulin resistance and prevent the risk of Type 2 Diabetes.


Furthermore, IF results are promising, however, longer and larger scale studies/trials need to be conducted to fully examine the benefits of fasting and if it can be recommended for the prevention and treatment of metabolic diseases.


Fasting is not for everyone, for some people fasting is great and beneficial, however, for others, fasting is difficult and can cause bad experiences. For some, fasting can cause hunger pains, irritability, anxiety, dehydration and daytime sleepiness.


Intermittent Fasting is not the best option if you suffer from an eating disorder, have diabetes or an impaired metabolism. Skipping meals may cause you to overeat or binge when you do get to eat. Women must be cautious if they decide to fast for an extended period of time as it can have a negative effect on hormones.

If women do decide to fast, it is suggested that they consume more saturated fats such as eggs and coconut oil.




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