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Intermittent fasting has been shown to increase metabolism, lower insulin resistance, reduce total cholesterol, triglycerides, LDL cholesterol, and positively affect the ghrelin (the hunger hormone). It has also been down to improve cognitive function and quiet neuroinflammation in the brain.

Liz Keller

Intermittent Fasting

Put simply, intermittent fasting is an eating pattern that cycles between periods of eating and periods of fasting. Unlike other “diets,” it doesn’t come with specifications on what to eat and what not to eat. Fasting has been shown to have multiple health benefits, but fasting has not shown the same benefits equally for men and women. If women try fasting without taking certain precautions, it can cause more harm than good.

There are typically two styles of intermittent fasting involving either daily 16-hour fasts or fasting for a full 24 hours, two times a week. Eating for 8 hours and fasting for 16 hours is usually the most comfortable and most sustainable, so it tends to be the more popular method.


Fasting has been used therapeutically since at least the 5th century BCE when Greek physician Hippocrates recommended abstinence from food or drink for patients who had specific symptoms. Some physicians recognized that patients with certain diseases naturally experience a loss of appetite, so they believed administering food during such states was unnecessary and possibly even detrimental. Fasting was thought to be an important natural part of the recovery process.


When appropriately done, intermittent fasting can be a simple way to lose weight because regular short-term fasts can help you consume fewer calories and shed pounds. People also find this way of eating can be easier to prep since there are fewer meals to plan and cook. The amount of weight a person loses while intermittent fasting will depend on the number of calories they consume during non-fasting periods and how long they adhere to the lifestyle. A 2018 review of studies in overweight adults found intermittent fasting led to an average weight loss of 15 pounds over 3–12 months. Studies done with pre-diabetic subjects also showed improvements in fasting blood glucose levels, weight, and waist circumference. However, research is still lacking regarding the impacts of intermittent fasting on other health behaviors, such as diet choices, sleep, and physical activity.

A new study examining the effects of fasting in mice found just 24 hours of calorie restriction flicks a metabolic switch that can boost the regeneration of stem cells in the gut. These intestinal stem cells fail to regenerate as effectively as people get older. They’re essential for helping us to maintain healthy tissue and fight off disease. The study found that fasting-induced the cells to break down fatty acids instead of glucose while simultaneously boosting the ability of the cells to regenerate themselves.

Intermittent fasting has been shown to increase metabolism, lower insulin resistance, reduce total cholesterol, triglycerides, LDL cholesterol, and positively affect the ghrelin (the hunger hormone). It has also been down to improve cognitive function and quiet neuroinflammation in the brain.


Intermittent fasting can have adverse effects on women. A woman’s reproductive function is connected to her metabolic function and vice versa. So anytime a woman’s body thinks it’s starving (like not eating for a while), it goes into survival mode, where it holds onto weight (to survive the perceived famine or apocalypse). It also increases the production of the hunger hormones ghrelin and leptin (so that you feel famished and rush to get as much food as possible as fast as possible) and slows down non-essential functions like reproduction (so you can keep yourself alive and not waste energy on growing a baby).


Intermittent fasting or alternate-day fasting is not a lifestyle choice for everyone. If your regular routine involves eating before your 6 am workout, there’s a good chance of fasting not fitting into your lifestyle. That is unless you plan on eating your last meal at 2 pm. However, if you find yourself habitually snacking late at night want to try to change your mindset about when you “need” to eat, it might be worth trying. It also is something to look into if you are looking for the benefits it offers for cardiovascular disease or diabetes.

Women can intermittently fast, but there are some suggestions to follow:

  • Don’t fast on consecutive days; instead, pick no more than two or three non-consecutive days in a week to practice intermittent fasting.
  • Don’t fast for more than 12 or 13 hours at a time, going any longer can trigger a negative hormonal cascade.
  • Don’t do intense workouts on fasting days.

Fasting is NOT recommended if you:

  • Have diabetes and are taking diabetes medication.
  • Have problems with blood sugar regulation.
  • Have low blood pressure.
  • Take medications.
  • Are underweight.
  • Have a history of eating disorders.
  • Are a woman who is trying to conceive.
  • Are pregnant or breastfeeding.

As with most “new” trends in nutrition, there are myths and confusion. I personally used to tell people, “breakfast is the most important meal of the day because it breaks your fast from the night before and gets your metabolism going.” Now studies on intermittent fasting are saying the exact opposite, “skip breakfast, and you will live longer.” While intermittent fasting may not be for everyone, I do think it can be beneficial for some. As with any style of eating, focusing on real, whole foods is the key to being healthy and eating smart!

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About the Author

Liz Keller

Liz Keller is a Nutritionist with a bachelor’s degree in Nutrition & Dietetics from Queens College and is currently pursuing her master’s degree in Human Nutrition from Bridgeport University. She is a certified CDC DDP Lifestyle coach and has experience working for a national weight loss and nutrition company and has also helped other fitness facilities establish nutritional programs with structured meal plans and client education.

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