Intermittent fasting has been gaining in popularity over the last few years. This is because there are lots of health benefits that come along with it. It’s often associated with keto or low-carb diets, but it’s a method that’s being used across all different dietary patterns. So, no matter how you choose to eat, it’s something you can try.
It’s important to note that intermittent fasting is not for everyone. If you are new to IF, please be sure to read through to the section on safety considerations. With that said, let’s jump right in with some intermittent fasting basics.
What is Intermittent Fasting?
Intermittent fasting is a pattern of eating that cycles between periods of feeding and periods of fasting. Typically, you shorten the feeding window and increase the fasting period. This is done to achieve health benefits like improved digestion and weight loss. More on that later in this post.
During the fasting period, foods are not permitted. Instead, you stick to calorie-free beverages like water and herbal tea until the feeding window begins. Drinking fluids helps to keep hunger at bay until it’s time to eat.
Keep in mind that you still need to pay attention to what you are eating during the feeding window. This isn’t a strategy meant to help keep you from gaining weight while noshing on big macs. What you eat during that window matters, so be mindful of that. Planning for good nutrition throughout your period of eating is just as crucial. Even more so for methods involving restricted calories during the feeding window.
The Stages of Digestion
We cycle through two stages of digestion, the anabolic stage and the catabolic stage. They cannot occur at the same time, so it’s important to know what each is responsible for.
The anabolic stage begins as soon as we being to eat. The body jumps into action and begins the process of digesting our food so we can absorb nutrients from it. You remain in this stage until there is nothing left to digest. This stage is very labour intensive for the body and requires a lot of effort. While digesting food, our body has to put off other essential processes.
The catabolic stage picks up where the anabolic stage leaves off. Once our food is digested, the body can move into repair mode. This is when the nutrients you eat are used to heal, repair and detoxify your body. However, this phase ends as soon as we begin to eat again.
The problem is, we tend to remain in the anabolic stage for most, if not all of our waking hours. If you tend to snack before bed, you’re remaining in this stage for part of the night as well. By not allowing the catabolic stage to take over, we’re robbing our body of time to heal and regenerate.
This is the basic idea behind intermittent fasting. Restricting your feeding window allows your body to get to that important rebuilding stage, and stay there for a while.
Types of Intermittent Fasting
There are many variations of intermittent fasting. Let’s go over some of the more popular methods.
In the 5:2 method, you eat normally for 5 days of the week. You then choose 2 non-consecutive days a week to significantly restrict calorie consumption. Typically to 500 calories for women, and 600 calories for men. Usually in two meals of 250-300 calories each.
The problem with this method is that it can be very difficult to sustain. Many experience headaches, irritability and trouble sleeping on fast days. Severe calorie restriction like this can lead some people to binge on normal feeding days. Thus negating their efforts.
There is also a lack of long-term scientific evidence surrounding this method specifically. Instead, it’s assumed that the benefits of other intermittent fasting methods apply to this one as well.
Note: This method is not safe for people with insulin-dependent diabetes. This is because fasting can trigger low blood sugar in diabetics. Please speak to your doctor before beginning any method of fasting.
This method involves fasting for 24 hours straight, on 2 non-consecutive days of the week. Resuming your normal eating patterns for the remaining 5 days.
On fast days, you stick to zero-calorie beverages like water and herbal tea. Diet soda is also permitted on this plan. For me, this is a huge red flag that this plan is more about weight loss than improving health. For the record, diet soda is not a beverage that should be part of ANY healthy eating plan.
This intermittent fasting method is also pretty difficult to sustain. Going 24 hours without anything to eat is difficult in today’s society, where food is everywhere you look. You may also experience side effects like headaches, weakness and irritability on fast days.
Another potential issue with this method is that the long fast window can lead to overeating or binge eating on non-fast days. This basically negates any benefits of the fast.
Note: This method is not safe for insulin-dependent diabetics, women who are pregnant, breastfeeding or trying to conceive, or anyone with a history of eating disorders. Please consult your doctor before beginning any type of fast.
This method is one of the most popular. It involves restricting the feeding window to 8 hours a day, followed by 16 hours of fasting. This is also commonly referred to as time-restricted feeding.
For example: If you eat your last meal of the day at 6pm, you’d then fast until 10am the next morning.
16/8 is the considered the easiest to follow and most sustainable method. This is because most of the fasting period falls over sleeping hours and first thing in the morning. Many people don’t have much of an appetite at these times anyway.
It’s also a more flexible approach to intermittent fasting. This is because you can choose your 8-hour window based on your schedule and what will work best for you. It’s also easy to ease into. Many people start with a shorter fasting window, like 12 hours, and slowly increase it over time. This allows you to listen to your body and follow what works for you. Some people will choose a 16 hour (or longer) fasting window. While some others will feel best with a shorter 14 or 15-hour fasting window.
For these reasons, this is the method that I practice myself. This is also the method I would suggest to others who are interested in trying IF.
Health Benefits of Intermittent Fasting
There are many health benefits associated with intermittent fasting. One of the main benefits is that it allows your body to remain in the catabolic (repair) stage for longer periods of time. Essentially, we are getting out of our own way. Letting our body follow it’s natural rhythm by refraining from constant eating.
Following this pattern of eating can naturally reduce your calorie intake. This can help with weight loss efforts. This is, of course, provided that you eat healthfully during your feeding window and don’t binge on junk food.
Intermittent fasting has also been found to increase insulin sensitivity. This offers some protection against type 2 diabetes. Used in conjunction with a whole food, plant-based diet (which can help prevent and reverse type 2 diabetes), the risk becomes pretty small.
Other benefits linked to intermittent fasting include reduced inflammation, boosted immune function, and improved brain function. There are also studies suggesting that intermittent fasting has anti-aging effects and can increase longevity.
Intermittent fasting is considered safe for healthy individuals. However, there are some factors to consider.
Some women may find longer fasts (or severe calorie restriction) can cause disruptions to their menstrual cycle. For this reason, it is not suggested to fast while pregnant, breastfeeding or trying to conceive. In general, women fare best on a shorter 14-15hr fasting window. Be sure to listen to your body so you can adjust if needed.
Intermittent fasting is not for everyone. It is not recommended for children, those who are underweight or have a history of disordered eating. It is also not advised for people on medications, people with low blood pressure or insulin-dependent diabetics
It’s important to consult your doctor before beginning any intermittent fasting regimen. They can help you decide whether this is a safe and healthy eating pattern for you.
The Bottom Line
Intermittent fasting can be done in different ways. I’ve covered the 3 most popular methods here. There are some encouraging studies suggesting many potential health benefits. However, it’s important to note that long-term studies are limited. It is considered safe for healthy individuals. However, you should seek out your doctor’s advice to ensure this is a safe option for you.
I personally feel that a 16/8 (or modified 16/8 for women) time-restricted feeding method is best. It offers a happy medium of health benefits, while avoiding some of the difficulties seen on the more drastic approaches.
Have you ever tried intermittent fasting? How’d it go? Let me know in the comments below.
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Related: What You Need to Know About Keto
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