Intermittent Fasting and Your Hormones


By. Dr. Maggie Ney

There is been so much excitement recently about intermittent fasting, (IF), and for good cause. New research studies suggest that intermittent fasting helps optimize insulin levels, promote weight loss, facilitate cellular repair and even control gene expression to promote longevity and disease protection. People who practice IF report feeling more energetic and wake with a feeling of alertness and excitement to start the day.

What is Intermittent Fasting?

Intermittent fasting is a term used to describe an eating pattern that sets aside a specific period of time during the day for eating while the rest of day is devoted to fasting.

What are the benefits of Intermittent Fasting?

Studies have shown that intermittent fasting:

  • Reduces insulin levels, which helps facilitate fat burning and balances blood sugar levels.
  • Reduce insulin resistance and lowers blood sugar levels – at least in men.
  • Raises Adiponectin – a key hormone that tells our body to burn fat.
  • Induces cellular repair, which allows cells to more efficiently remove waste from cells.
  • Increases growth hormone levels, which further facilitates fat burning and muscle gain.
  • Reduce oxidative stress, which is a major contributor to the aging process.
  • Reduce inflammation. Inflammation is now recognized as the cause of chronic diseases such as heart disease and dementia.
  • Controls gene expression by turning on some genes while turning off the expression of other genes. The result of this manipulation of gene expression is increased longevity (ex: turning on SIRT1 gene and turning off mTOR gene).
  • Triggers autophagy – the process by which cells cleanse, detoxify and remove waste   material from cells.
  • Prevents cancer in animal studies. One paper shows that IF can reduce side effects caused by chemotherapy.
  • Increases new neuron formation in the brain, which support brain health. This new neuron formation coupled with Intermittent Fasting’s anti-inflammatory effects provides even more potential defense against dementia.

How is intermittent fasting scheduled during the day and week? 

There is not a one size fits all protocol for intermittent fasting. Each person responds differently to how many hours they fast and how often they practice IF during the week. It does take some experimenting in the beginning to see if IF is right for you and which protocol allows your body to thrive.

The most common schedules are:

  • The Leangains Protocol (also known as the 16/8 method – involves restricting your eating period to an 8-hour period, for example 11AM -7PM. For many people we recommend lengthening the eating period to 12-hours (7AM – 7PM). This can be done 2 or more times a week.
  • Eat-Stop-Eat – fasting for 24-hours once or twice a week. For example, no eating from dinner one day until dinner the following day.
  • The 5:2 Protocol – involves only eating 500-600 calories on 2 nonconsecutive days of the week, for example every Monday and Wednesday.

Does Intermittent Fasting affect women differently than men.

Yes! A woman’s physiology is different than a man and we know that men and women respond to fasting differently. Women are quite sensitive to periods of fasting. If intermittent fasting is not done correctly, it can contribute to hormonal imbalances. When a woman’s body senses she is in a state of starvation, the hunger hormones levels, ghrelin and leptin, are affected. These hormones can more easily trigger a woman to binge, which is often followed by periods of restricting and then binging again. This patterns leads to an unhealthy relationship with food and a more critical body image.

Fasting can also interfere with ovulation. A woman’s body is wise and when it senses that there may not be enough food available, hormones shift in a way that can inhibit ovulation thus preventing pregnancy. In a biological sense, when the body senses starvation it knows it is not the right time to get pregnant.

For women interested in receiving the benefits of IF in the most healthy way, I generally recommend a 12 -16 hour fast on 2 nonconsecutive days a week. For example, fast between 7PM -7AM on Tuesdays and Thursdays. And, on those days, I encourage avoiding strenuous exercise and embracing more gentle forms of exercise such as restorative yoga and walking. Generally after 2-weeks most women (and men too) will know if Intermittent Fasting is right for them and which schedule feels best.

And, of course, benefits of intermittent fasting are increased when you consume mostly nutrient dense, whole foods, during your time of eating.

If you are interested in learning more about intermittent fasting and to discuss the best schedule for your body and your lifestyle, let us help you.

Dr. Maggie Ney is the Co-Director of the Women’s Clinic, you can make an appointment with her by emailing or calling 310-451-8880