Fasting, especially intermittent fasting (IF), is all the rage right now. And, for many, it’s really helpful and works really well. But…it’s not for everyone and the down sides of fasting are rarely spoken about. Particularly, how fasting can be affected by chronic stress is often missed in the pro-fasting information.
So, that’s what I’m going to do—I want you to know the dark side of fasting so you can see if it’s right for you and your amazing body. The most important thing to know about IF is that it affects men and women very, very differently.
Proponents of fasting always quote research, but did you know that most of the research was done only on men? Out of 71 studies on intermittent fasting, only 13 included women. There are no controlled studies that specifically looked at how fasting affects women.
In a nutshell, fasting is a stress on the body and it can increase cortisol levels. For some, that will give a boost of energy, clear thinking, and a great overall feeling. But for those who are already dealing with a lot of stress or who deal with high cortisol already, fasting can be a big-time problem. I’ve found that women’s bodies are much more sensitive than men’s to the cortisol effects of fasting.
Also, benefits like a boost in metabolism, better hormone balance and better energy have only been shown in men. But since the gender difference isn’t spoken about, many women blame themselves when IF doesn’t work for them. I’ve worked with dozens of women who’ve had detrimental effects from fasting but continued, hoping the benefits would come eventually. Women may have upwards of a 50% increase in cortisol and less insulin sensitivity when fasting! This means after fasting, the body might be more insulin resistant. Woah. Combine fasting with all of the other stressors in our day-to-day life and it can become too much.
We’re already living in a high cortisol world! Between the constant dinging of our phones, work stress, family stress and the harried nature of life today, the last thing we need to add is more cortisol to our day.
Women in perimenopause and menopause are even more affected because their cortisol levels tend to be higher due to lower estrogen. This means their bodies will react strongly to any increase in cortisol, including fasting.
Fasting can also reduce precious estrogen even faster, leading to more intense symptoms like brain fog and hot flashes. A drop in estrogen can also increase your appetite… which is the opposite of what you’re trying to accomplish with fasting. In a nutshell, fasting, including IF, isn’t a perfect solution for everyone and is extra complicated in a woman’s body because it’s more sensitive to changes in energy balance. This difference is louder if any other stressors are also playing out (work, home, kids, financial, etc.).
Should you try fasting? Maybe, if it seems interesting and you keep checking in to see if your body likes it. If it feels good or easy, then it’s probably working for you. If you’re having to find food hacks to get through the fasts, your energy is lower, or you just don’t like it… well, it’s probably time to stop because it may cause weight gain.
If you’re looking at IF to lose weight but you’re concerned about the stress in your life, lowering your cortisol level first might be much more effective than fasting. Look at the chart below for few easy ways to calm the cortisol that’s flowing through your body. The most important thing to remember when embarking on anything new is to stay in touch with your body. Does this feel good? Does this feel easy? If you answer “no” to either question, try something else and see how that feels. Your body is your best ally in your health—always listen to what it has to say!
