What is IF?
Intermittent Fasting (IF) is an eating pattern that cycles between periods of fasting and eating.
Fasting has been a practice throughout human evolution. As ancient hunter gatherers didn’t have access to food at all times, humans evolved the ability to function without food for extended periods of time.
Fasting can even be seen as more natural than eating three or more times a day.
There are several ways of doing IF.
16/8 involves restricting your daily eating period to 8 hours, then fasting for 16 hours in between. For example, fitting all your meals between 1pm to 9pm (basically, skipping breakfast).
Many people find this to be the simplest and easiest IF method to stick to.
One Meal A Day (OMAD) involves eating all your calories in one meal. For example, eating dinner then not eating until dinner the next day. This usually amounts to 23 or 24 hours of fasting per day.
With this method, you consume only 500-600 calories on two non-consecutive days of the week, but eat normally the other five days.
You don’t have to stick to these three methods. You could do 20/4 instead of 16/8 (fast for 20 hours, eat for 4), or any other schedule that suits you best.
The levels of human growth hormone (HGH) skyrocket, increasing as much as five-fold. This has benefits for fat loss and muscle gain, to name a few.
Insulin sensitivity improves and levels of insulin drop dramatically. Lower insulin levels make stored body fat more accessible. It can also lower blood sugar by 3-6% and fasting insulin levels by 20-31%, which protects against type 2 diabetes.
When fasted, your cells initiate cellular repair processes. This includes autophagy, where cells digest and remove old and dysfunctional proteins that build up inside cells.
By making you eat fewer meals, IF can lead to an automatic reduction in calorie intake. In addition to the increase in HGH and lowered insulin levels, it increases the release of noradrenaline, a fat burning hormone.
Some studies show reductions in markers of inflammation, a key driver of many chronic diseases.
IF may reduce “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance - all risk factors for heart disease.
Animal studies suggest that IF may prevent cancer.
IF increases the brain hormone BDNF and may aid the growth of new nerve cells. It may also protect against Alzheimer’s disease.
Longevity & anti-aging
There are changes in the function of genes related to longevity and protection against disease.
IF can also extend lifespan in rats. Studies show that fasted rats lived 36-83% longer than unfasted rats. Of course, we have to take into account that this was a study on rats and not humans.
Simpler and easier to stick to
IF is also very easy to stick to, and perfect for the busy individual.
You only have to think about one or two meals per day - this means you don’t need to meal prep and carry meals around with you.
You can also just have your meals and be done with them for the day, not having to think about food or cooking until the following eating window.
Who shouldn't do IF?
While IF is very beneficial, it isn’t for everyone.
While your body adjusts to the new eating pattern of IF, you may feel weak and your brain might not perform as well as you’re used to. This is just temporary, but you should consult with your doctor before trying IF, especially if you:
- Have diabetes
- Have problems with blood sugar
- Have low blood sugar
- Take medications
- Are underweight
- Have a history of eating disorders
- Are pregnant or breastfeeding
That being said, there is nothing dangerous about IF if you’re healthy and well-nourished overall.
How to start
Fasting may sound intimidating, but it’s actually very simple. If you’ve ever eaten dinner then slept late and not eaten until lunch the next day, you’ve probably fasted for 16+ hours.
Some people instinctively eat this way as they don’t feel hungry in the morning.
As we previously mentioned, 16/8 fasting is the simplest and most sustainable way of intermittent fasting, so you may want to start with this.
If 16/8 is too difficult at first, then start with 14 hours fasting, and a 10 hour eating window instead, and gradually shorten your eating window.
If you feel good, you can move on to 20/4, and even OMAD (One Meal A Day).
Another approach is to simply fast when it’s convenient - just skip meals from time to time when you’re not hungry or don’t have time to cook. There is no need for a structured IF plan to derive at least some of the benefits.
Basically, experiment with different approaches and find something that fits your schedule and that you enjoy!