Humans throughout history have feasted and then fasted in regular intervals, sometimes by choice (the ancient Greeks were known to fast) and sometimes by necessity. Some cultures and religious groups still practice periods of fasting today. Our bodies were built to respond and adapt to this type of nourishment (and lack thereof) for periods of time. For a number of reasons, fasting practices became less popular over time, until pretty recently.
For most of civilization, we lived without grocery stores, restaurants, convenience stores and meal or grocery delivery services. Now that we have these novelties, we can (and do!) eat during every waking minute because it is convenient. Conventional wisdom (and diet culture) has also taught us that eating smaller meals throughout the day can kick your metabolism into high gear and allow you to lose weight more effectively since you are constantly “stoking the fire”. When you look at how our bodies work in response to what we put into it, research shows that the opposite is actually true. We are better off giving our digestion a break sometimes.
The more often we eat, the more often the pancreas needs to release insulin to regulate blood sugar. With more ups and downs, this blood sugar roller coaster can lead to irritability and mood swings, increased cravings, and even more fat storage. The body no longer needs to use fat stores to fuel the body between meals, but instead uses whatever is coming in, usually in the form of glucose. Whatever is not going to be utilized right away is stored as fat. Additionally, each time food enters our body, the process of digestion is kicked off all over again and energy is allocated to breaking down that food which takes away from other tasks that are required by the body for other purposes.
Ideally, we should have a fairly steady blood sugar ride throughout the day with balanced meals of fat, protein and carbs to satiate us until our next meal. We should not constantly rely on food for a quick hit of energy. This is not to say that eating regularly or snacking is bad, but giving your body a minimum of 3-4 hours between eating can provide the digestion cascade with the rest it needs and be very beneficial to the body.
So, what is it?
Intermittent fasting is a practice in which you choose to forgo food for a pre-determined period of time between meals, typically between your last meal of the day and whenever you decide to eat again (usually the following day). This process enables your body to enter a prolonged fasted state whereby it utilizes or burns fat stored on the body for fuel. You experience a longer period of low insulin in the blood as opposed to the constant switching of low to high and back when you your body is constantly taking in food.
Over time, this type of fasting may encourage your hormones to reset and return markers such as blood glucose, blood pressure and liver function to normal levels. It may also allow you to better recognize hunger cues and bring about a better relationship with food. Some research has shown that intermittent fasting can help to prevent modern health problems like diabetes, heart disease, stroke, cancer, fatty liver, Polycystic Ovarian Syndrome (PCOS), and even dementia and Alzheimer’s.
Women and Intermittent Fasting
All of the benefits sound great, but almost all of the research done on this topic is with men (are you surprised?), rats, or the women participants did not experience the same positive results as the men did. In fact, as of now, there are no intermittent fasting studies using only women. Furthermore, the studies that have been done on humans haven’t gone beyond researching body weight or cardiovascular benefits. Women are very different, we have completely different hormones and nutritional needs then men. Anecdotally, some women who practice intermittent fasting report low energy, sleeplessness, anxiety and stress, irregular periods, hormone imbalance and brain fog. This raises a red flag for me.
It makes a lot of sense why women in particular might feel this way. Fasting, which is a stressor to the body in itself, signals your brain (and your body) that it is in famine mode. For women, this may prompt the body to halt ovulation until the stress on the body dissipates and the nourishment entering the body is at a sufficient level to support reproduction and sustain another life. This may be true for men also, but biologically women are much more sensitive to these effects.
Is it right for me?
I am not saying that women should never practice intermittent fasting. What I am saying is that we are all bio-individual, what works for one person may or may not work for someone else. This goes for both men and women. We all need to read the signs our own bodies gives us to determine what diet and lifestyle practices will make us feel the best. It is definitely more challenging for women to intermittent fast, but it could be a tool worth trying try in order to heal your relationship with food, balance your hunger hormones, or use it for therapeutic reasons. If you are trying to have a baby, planning on trying, pregnant, are a nursing mom or have a history of disordered eating, intermittent fasting is not appropriate. If you struggle with blood sugar issues, I recommend working with a practitioner work through the issues and get your body to burn fat for fuel, before starting a fasting practice. Fasting will only cause you more harm than good if your body is unable to tap into its own fat stores. Many different types of intermittent fasting practices exist, some with benefits backed by research and others not, but there are only a couple of ways that I believe are appropriate for women (and of course men too!) given our general make up and evidence of its validity.
1. Overnight fasting: This one is the easiest to implement and the one I recommend most. It involves fasting for 12 to 16 hours at a time 4-7 days per week. For example, you stop eating at 7:00 PM and fast until sometime between 7:00 AM and 11:00 AM the next morning. This practice can actually be as simple as not eating anything after dinner, and skipping breakfast. For people wake up hungry and like to eat breakfast, this can be a challenging transition.
To help extend your fast later into the morning, drinking coffee or tea with some added fat (Bulletproof style), but no sweetener will help your blood sugar stable and your hunger pangs at bay until you are ready to eat a meal. You may end up eating only two meals a day with this type of fast and it is important to eat nutrient dense, healthy foods during your eating window to ensure you are getting enough of the proper nutrients your body needs.
The time you break your fast is flexible and depends on when you feel hungry. You may want to start with 12 hour fast and over time, lengthen your fasting window. This type of intermittent fasting still allows you to give your digestion a rest, potentially burn fat, and restore your hormone balance, but it won’t restrict calories long enough to cause your body additional problems. Always be sure to drink plenty of water (you can even add a pinch or two of salt to your water – my favorite is Real Salt) while you are fasting. I find that this type of fasting (when I practice it) works the best for me and I find it to be the most natural for my body and lifestyle.
2. Spontaneous Meal Skipping: You can still reap the benefits of intermittent fasting without actually doing anything structured. This practice involves simply skipping a meal from time to time, when you don't feel hungry, travelling across time zones or are too busy to cook and eat. It is a myth that people need to eat every few hours or they will hit starvation mode or lose muscle mass. As I mentioned before, we are well equipped to handle periods of not eating so skipping a meal now and again will not only not be harmful, but can be beneficial. I find this type of fast to be easy to implement and pretty natural for the body. If preparing and eating a healthy meal is going to cause you stress, or you are travelling and there are simply no good options, or maybe you are trying to adjust to a new time zone, skipping a meal may be very appropriate. Again, just make sure that when you do eat again, you are refueling with high quality, nutrient dense foods.
Intermittent fasting is definitely not for everyone. It is not something that you need to do for your own health, it is just another tool in the toolbox that can be useful for some people. Generally, men tend to do better with longer fasting windows and fasting more often than women do. When in doubt or if you want to try something new, I always recommend working with a practitioner who can help you to work through what is best for you and your health.
- https://www.ncbi.nlm.nih.gov/pubmed/24268866 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC156352/