What is Intermittent Fasting?
Most people have heard of intermittent fasting at this point, but have you heard of time-restricted eating? Let’s look at both and compare what the benefits may be for you.
Intermittent fasting has been a trend for several years now but has been practiced for religious, health, and cognitive reasons recorded back before the ancient Greeks.
From a healing standpoint, the ancient Greeks believed that the body was better able to focus on healing the illness when it was devoid of food. They also believed that brain function was greater when they practiced fasting. If you think about it, do you feel energized and highly cognitive when you are full, or do you tend to slow down physically and mentally? I think they were on to something! (Did you know that many animals instinctively fast when they are sick?)
What does fasting look like?
Intermittent fasting was popularized in 2012 by BBC broadcast journalist Dr. Micheal Mosley’s documentary, Eat Fast, Live Longer, followed by a book, The Fast Diet. In 2016 Jason Fung wrote the bestseller, “The Obesity Code,” which shed light on the effectiveness of fasting on insulin and weight loss.
Here are some popular ways of intermittent fasting:
5:2 = eating “normally” 5 days and restricted calorie intake for 2
Eat, Stop, Eat = this involves a 24 hour fast, once or twice a week
Alternate day fast = every other day fasting, either fully or very restricted calorie intake
And finally, 16/8 = 16 hours fast with an 8-hour eating window.
The last one is also considered time-restricted eating, and what I would like to spend most of my time discussing. The reason is that I personally find this to be what works for me. I sleep better, I feel more energized and alert, and when I do have a weekend filled with dinners out or get-togethers, I can enjoy myself without concern, or feeling like “I blew it” and getting derailed.
A few years ago when I heard about intermittent fasting, I was a skeptic because my training had taught me to eat within an hour of waking, to “jump-start” my metabolism. (Remember the old saying, “breakfast is the most important meal of the day”?) I felt that fasting was just a way to reduce calories, and I had no real evidence otherwise. After trying time-restricted eating, as well as spending a good bit of time researching, I am now a fan! But it is not for everyone.
The most popular time-restricted eating is a 16-hour fast and 8-hour eating window. For me, that usually looks like eating between 12:00 and 8:00.
Some of the theories are that when we have food that needs to be digested, the blood flow goes to the digestive organs and not to the cells that need repair and growth, so we don’t get the restorative sleep we need. Restful sleep is important for muscle repair, protein synthesis, tissue growth, and hormone release as well as detoxification of cells and for our memory. When we fast, we get significant reductions in blood sugar and insulin levels, as well as an increase in human growth hormone. When we eat too close to going to sleep, there is also a chance of blood sugar spike which can disrupt our sleep patterns, and as we age, there are many other factors that can disrupt sleep……so why add to them? After a blood sugar spike, there will usually be a period of lower blood sugar or maybe even hypoglycemia which will cause you to want, and maybe even need, to eat first thing in the morning. So avoiding the food that can cause this spike and drop is important.
Does time-restricted eating help you lose weight?
I believe so, I have seen it happen. Let’s look at the hormones associated with maintaining a healthy weight and also sleep. Hunger hormones ghrelin, which increases hunger, and leptin which increases the feeling of being full, are both affected by sleep. During sleep, ghrelin decreases because you are using less energy than when you are awake. When you lose sleep, however, your ghrelin increases which then suppresses leptin. This imbalance makes you hungrier during the day and can cause you to overeat.
Melatonin is a hormone in your body that plays a role in sleep. The production is connected to the time of day, increasing when it gets dark and decreasing when it gets light. Some research has shown that melatonin has an effect on our insulin levels, meaning that if you eat too early or too late in the day you could possibly be insulin resistant during those times, resulting in more storage of fat. Waiting longer in the morning will give the melatonin a chance to lower.
I believe fasting can be a good way to reset, heal, bring down inflammation, boost brain function, and much more. The way you fast is totally up to you, and what works for you and your lifestyle. For me, eating between 12:00-8:00 works, and is not stressful to my body, or to me emotionally, so it is what I choose to do. There are situations when I change the timing of my eating window because of a social engagement, crazy workday, or other various reasons. I do, however, try my best to plan ahead! With all fasting, your goal should be to eat a healthy diet during eating times, and plenty of water during fasting times. If you feel you are overeating, choosing unhealthy foods, or even binge eating, I would recommend you stop fasting. If you have existing eating disorders, I do not recommend fasting at all but do suggest seeking professional help.