Intermittent fasting is currently one of the world's most popular health trends.
People are using it to:
- Lose weight
- Improve their health
- Simplify their lifestyle
A lot of studies show that it can have tremendously powerful effects on your body and brain, and in some cases to help you live longer. (The said study.)
This is the ultimate comprehensive step-by-step guide to intermittent fasting.
What is Intermittent Fasting in essence?
Simplifying everything, intermittent fasting is an eating pattern that cycles between periods of fasting and eating.
The interesting thing is that it doesn't specify what type of food you should eat, but it rather focuses on when you should eat.
In this respect, it's not a conventional diet but more of an eating pattern. There are a lot of different types of intermittent fasting methods which we'll discuss below.
Fasting has really been a practice throughout human evolution. Ancient hunter-gatherers didn't have supermarkets or available food year-round. Sometimes they couldn't find anything to eat and as a result, humans evolved to be able to function without food for periods of time.
Additionally, fasting is often done for religious and spiritual reasons, including Islam, Christianity, Judaism, and Buddhism.
Methods of Intermittent fasting
There are several ways of doing intermittent fasting — all of which involve splitting the day or week into fasting periods.
During those fasting periods, you either eat very little or nothing at all.
The three top and mos popular methods are:
- 16/8 method: Also known as Leangains protocol. It involves skipping breakfast and restricting your daily eating period to 8 hours. You can choose something like 1-9 pm. Then, you have to fast for 16 hours in between and eat nothing at all.
- Eat-Stop-Eat: Involves fasting for 24 hours, once or twice a week depending on your choice. For example, not eating from dinner one day until dinner the next day.
- 5:2 diet: With this method, you'll consume only 500-600 calories on two-non consecutive days of the week, and eat completely normal the other 5 days.
By reducing the calories you intake, all these methods help tremendously in weight loss as long as you don't eat much more during the eating periods.
Most people feel like the 16/8 method is the simplest and most sustainable one to stick to.
How does it affect your cells and hormones
When you fast, a lot of things in your body happens on the cellular and molecular level.
For instance, your body has to adjust the hormone levels to make stored body fat more accessible.
Also, your cells initiate important repair processes and change the expression of genes.
Here are a few changes that happen in your body when you fast:
- Human growth hormone: The levels of growth home skyrockets, and it increases as much as 5-fold. This is actually good for fat loss and muscle gain, according to this article.
- Insulin: The insulin sensitivity improves and levels of insulin will drop down drastically. This is good because lower insulin levels make stored body fat more accessible.
- Cellular repair: When you fast, your cells initiate cellular repair processes. This will include autophagy, which is the process where the cells digest and remove the old proteins that build up inside cells.
- Gene expression: There are changes in the genes too, genes related to longevity and protection against diseases to be more precise.
A powerful weight loss tool
Weight loss is probably the most common reason why people try intermittent fasting.
By making yourself eat fewer meals, it can lead to an automatic reduction in calorie intake.
In addition, intermittent fasting will change hormone levels to facilitate weight loss.
Additionally, it increases the release of the fat-burning hormone, which is also known as norepinephrine (noradrenaline).
And because of these changes in hormones happen, short-term fasting also increases your metabolic by 3-14% rate according to this article.
Also, by helping you eat fewer and burn more calories than you intake, intermittent fasting will cause weight loss by changing both sides of the calorie equation.
According to a study way back in 2014, it found that this eating pattern can cause 3-8% weight loss over 3-24 weeks, which is a tremendously high amount compared to other weight loss studies.
But, you have to keep in mind that the main reason that the intermittent fasting works is that it helps you eat fewer calories overall. If you keep on a binge and eat massive amounts during your eating periods, you will not lose weight at all.
Most studies have been done on intermittent fasting, in both animals but also in humans.
The studies have shown that it can have powerful benefits for weight control and also have a great impact on the health of your body and brain.
Here are some of the benefits of intermittent fasting:
Weight loss: As mentioned above, it helps you lose weight and belly fat without having to restrict calories consciously.
Insulin resistance: It can reduce insulin resistance, lower blood sugar by 6% and fasting insulin levels 20-30%, which would protect you against type 2 diabetes.
Inflammation: Some studies proved that it helps in reductions in markers of inflammation, which is a key driver of many chronic diseases.
Brain health: Intermittent fasting also increases the brain hormone BDNF and may aid the growth of new nerve cells. It also showed signs of protecting against Alzheimer's based on this article.
Anti-aging: Additionally, it can extend lifespan in rats. And the studies showed that fasted rats lived 37% up to 83% longer!
Note: Please keep in mind that researches are still in early stages, and most of the were small and short term. Most questions are yet to be answered.
Safety and side effects
Stating the obvious, hunger is the main side effect of intermittent fasting.
But, you might also feel weak and your brain might not perform the same as you're used to.
This is temporary because it takes time for your body to adapt to the new meal schedule. If a considerable portion of time goes by and you still feel weak, it's best to consult a doctor.
If you have a medican condition, you should consult with your doctor before taking any further steps in intermittent fasting.
- This is particularly important if you:
- Have diabetes
- Have problems with blood sugar
- Have low blood pressure
- Take medications
- Are underweight
- Are a woman who is trying to conceive
- Are pregnant and breastfeeding
All that being said, intermittent fasting does have an outstanding safety profile. There is nothing dangerous about not eating for a while, as long as you're healthy!
Frequently asked questions
Here are some of the most common questions about intermittent fasting.
Can I drink liquids during the fast?
– Yes. Water, coffee and tea and pretty much any other non-caloric beverage is fine. Just keep in mind that you don't add sugar to your coffee and you're good to go.
Is it unhealthy if I skip breakfast?
– No. The problem is that most breakfast skippers have unhealthy lifestyles. If you make sure to eat purely healthy food for the rest of the day, then feel free to skip breakfast.
Can I take supplements while fasting?
– Yes. But, keep in mind that some supplements have fat-soluble vitamins, and may work better if they're taken with meals.
Can I work out while fasting?
– Yes. Absolutely, fasted workouts are fine. Some people even recommend taking branched-chain amino acids before a fasted workout, so you should try it.
Should kids fast?
– Allowing your kid to fast is probably not such a good idea. It's best if you consult with your doctor about this matter.
Will fasting slow down my metabolism?
No. In fact, studies show that short-term fasts actually boost metabolism. But, longer fasts of 3 or more days might impact on slowing down your metabolism.