Intermittent fasting (IF) seems to be on everyone’s tongue today when talking about food and diet. The common question being, how do you do it and is it healthy for you? IF is simply timed eating followed by a period of not eating or drinking anything except water. The goal is to upregulate your body’s ability to burn fat for fuel. One of the benefits of being a modern human is access to food all the time.
However, humans should not eat all the time and benefit from periods of fasting. When we eat frequently, especially foods high in refined carbohydrates, we set the stage for developing insulin resistance and an inability to switch easily to burning fat because our bodies become so accustomed to burning sugar. It is healthy to have a period of at least 12 hours without eating or drinking, allowing your body to use of available sugar for energy, switching over to burning fat when the sugar is used up.
It is best to keep your eating times within an 8 -10 hour window to support metabolic flexibility and insulin sensitivity. This is the simplest technique for IF, and there are a variety of others such as eating normally for 5 days while restricting your window of eating on days 6 and 7, fasting for a complete 24 hour cycle one day a week while eating normally the other 6, and fasting every other day aiming to consume under 1000 calories on fasting days. I believe the most effective and healthy technique is following IF daily, following our normal circadian rhythms, keeping that window of eating to 8 or 10 hours of the day.
Sound challenging? It is in the beginning. You can experience drops in blood sugar during the night, causing you to wake up as cortisol is released into circulation, pulling sugars out of tissue storage for energy. You can also experience increased sugar cravings and headaches as your body adjusts and improves its fat burning capability.
It is easier to slowly ease into IF by pushing off breakfast 15-30 minutes each week for a couple of weeks while finishing your last meal or snack 15-30 minutes earlier as well. The goal is to aim for your window of eating to be somewhere between 9 am and 6 pm. The only thing you want to consume outside of your eating window is water. This is because each body is so unique it is almost impossible to tell what substances initiate the creation of sugar (gluconeogenesis) in your body for fuel. Water ensures you begin to switch over to burning fat and over time keep burning fat longer.
A couple of tips to help support your body transition back to burning fat for energy:
- Make your last meal or snack a food high in fat or protein. This will keep the food in your system longer and reduce blood sugar and insulin spikes, helping you switch to burning fat more quickly. I recommend a handful of nuts or a hard-boiled egg as your last snack.
- Make the first meal or snack you eat in the day a fat or protein. This will also prolong your body’s reliance on fat for fuel until you introduce carbohydrates later in the day. Eggs for breakfast are a good thing!
- Drink a lot of water. Water will help keep you full and hydrated, supporting the biochemical processes of burning fat as fuel. Adding a slice of fresh lemon to your water during the day helps your liver release fat stores more easily.
- Use L-carnitine as a supplement. L-carnitine is an amino acid that helps shuttle fatty acids in and out of cells and may help your body burn fat for energy more effectively.
If this sounds like a horridly rigid way of eating, remember that for 100’s of years humans relied on metabolic flexibility to survive during times of famine and food scarcity. Even in our modern era, before the emergence of grocery stores and fast-food restaurants, most people ate only during the daylight hours.
Despite our modern conveniences, we are still biological beings that thrive on our natural tendencies particularly where feeding is concerned. IF reminds us of this and is a great way to restore our metabolic flexibility and improve blood sugar control. It is also a way to improve the nutrition value of our food by eating healthy, nourishing whole food and kicking the processed food out!