What is intermittent fasting and Why it is important to do it and How to do it

What is intermittent fasting and Why should we do it

Intermittent fasting (IF) is a term for an eating pattern that cycles between periods of fasting and eating.
It does not say anything about which foods you should eat, but rather when you should eat them.
In this respect, it is not a “diet” in the conventional sense. It is more accurately described as an “eating pattern.”
Common intermittent fasting methods involve daily 16 hour fasts, or fasting for 24 hours, twice per week.
Humans have actually been fasting throughout evolution.
When you think about it, our hunter-gatherer ancestors didn’t have supermarkets, refrigerators or food available year-round. Sometimes we couldn’t find anything to eat, and our bodies evolved to be able to function without food for extended periods of time.
If anything, fasting from time to time is more “natural” than constantly eating 3-4 (or more) meals per day.

Bottom Line: Intermittent fasting (IF) is a term for an eating pattern that cycles between periods of fasting and eating. It is currently very popular in the health and fitness community.

How to do Intermittent Fasting

Intermittent fasting has been very popular for many years and several different methods have been used.
All of them involve splitting the day or week into “eating periods” and “fasting periods.” During the fasting periods, you eat either very little or nothing at all.
These are the most popular methods:

• The 16/8 Method: Also called the Leangains protocol, it involves skipping breakfast and restricting your daily eating period to 8 hours, for example from 1 pm to 9 pm. Then you “fast” for 16 hours in between.
• Eat-Stop-Eat: This involves fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day.
• The 5:2 Diet: On two non-consecutive days of the week, only eat 500-600 calories. Eat normally the other 5 days.

By making you eat fewer calories, all of these methods should make you lose weight as long as you don’t compensate by eating much more during the eating periods.
I’ve personally found the 16/8 method to be the simplest, most sustainable and easiest to stick to. It is also the most popular.

The 16/8 Method involves fasting every day for 14-16 hours, and restricting your daily “eating window” to 8-10 hours. Within the eating window, you can fit in 2, 3 or more meals.This method is also known as the Leangains protocol, and was popularized by fitness expert Martin Berkhan.
Doing this method of fasting can actually be as simple as not eating anything after dinner, and skipping breakfast. For example, if you finish your last meal at 8 pm and then don’t eat until 12 noon the next day, then you are technically fasting for 16 hours between meals.
It is generally recommended that women only fast 14-15 hours, because they seem to do better with slightly shorter fasts.
For people who get hungry in the morning and like to eat breakfast, then this can be hard to get used to at first. However, many breakfast skippers actually instinctively eat this way.
You can drink water, coffee and other non-caloric beverages during the fast, and this can help reduce hunger levels.It is very important to eat mostly healthy foods during your eating window. This won’t work if you eat lots of junk food or excessive amounts of calories.
Further reading on the 16/8 method: The Leangains Guide.
This guide is written mostly from a bodybuilding perspective and also involves weight lifting and supplementation, but the program can be adapted to suit any lifestyle.
I personally find this to be the most “natural” way to do intermittent fasting. I eat this way myself and find it to be 100% effortless.

Bottom Line: The 16/8 method involves daily fasts of 16 hours for men, and 14-15 hours for women. On each day, you restrict your eating to an 8-10 hour “eating window” where you can fit in 2-3 or more meals.

How Intermittent Fasting Affects Your Cells and Hormones

When you fast, several things happen in your body on the cellular and molecular level.
For example, your body changes hormone levels to make stored body fat more accessible.
Your cells also initiate important repair processes, and change the expression of genes.
Here are some changes that occur in your body when you fast:

• Human Growth Hormone (HGH): The levels of growth hormone skyrocket, increasing as much as 5-fold. This has benefits for fat loss and muscle gain, to name a few (4, 5, 6, 7).
• Insulin: Insulin sensitivity improves and levels of insulin drop dramatically. Lower insulin levels make stored body fat more accessible (8).
• Cellular repair: 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 (9, 10)
• Gene expression: There are changes in the function of genes related to longevity and protection against disease (11, 12).

These changes in hormone levels, cell function and gene expression are responsible for the health benefits of intermittent fasting.

Bottom Line: When you fast, human growth hormone levels go up and insulin levels go down. Your body’s cells also change the expression of genes and initiate important cellular repair processes.

Intermittent Fasting is a Very Powerful Weight Loss Tool

Weight loss is the most common reason that people try intermittent fasting (13).
By making you eat fewer meals, intermittent fasting can lead to an automatic reduction in calorie intake.
Additionally, intermittent fasting changes hormone levels to facilitate weight loss.
In addition to lower insulin and increased growth hormone levels, it increases release of the fat burning hormone norepinephrine (noradrenaline).

 Because of these changes in hormones, short-term fasting may actually increase your metabolic rate by 3.6-14% (14, 15).
By helping you eat less (fewer calories in) and helping you burn more (more calories out), intermittent fasting causes weight loss by changing both sides of the calorie equation.
Studies show that intermittent fasting can be a very powerful weight loss tool. In a review study from 2014, it was shown to cause weight loss of 3-8% over periods of 3-24 weeks (1).
That is actually a very large amount compared to most weight loss studies.
According to this study, people also lost 4-7% of their waist circumference (1). This indicates that they lost significant amounts of the harmful belly fat that builds up around the organs and causes disease.
There is also one study showing that intermittent fasting causes less muscle loss than the more standard method of continuous calorie restriction (16).
However, keep in mind that the main reason this works, is that it helps you eat fewer calories overall. If you binge and eat massive amounts during the eating periods, then you may not lose any weight at all.
Read this article for more information on IF and Weight Loss.

Bottom Line: Intermittent fasting may boost metabolism slightly, while helping you eat fewer calories. It is a very effective way to lose weight and belly fat.

Health Benefits of Intermittent Fasting

Many studies have been done on intermittent fasting, in both animals and humans.
These studies have shown that it can have powerful benefits for weight control and the health of your body and brain. It may even help you live longer.

Here are the main health benefits of intermittent fasting:

• Weight Loss: As mentioned above, intermittent fasting can help you lose weight and belly fat, without having to consciously restrict calories (1, 13).
• Insulin resistance: Intermittent fasting can reduce insulin resistance, lowering blood sugar by 3-6% and fasting insulin levels by 20-31% (1). This should protect against type 2 diabetes.
• Inflammation: Some studies show reductions in markers of inflammation, a key driver of many chronic diseases (17, 18, 19).
• Heart Health: Intermittent fasting may reduce LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance. These are all risk factors for heart disease (1, 20, 21).
• Cancer: Animal studies suggest that intermittent fasting may help prevent cancer (22, 23, 24, 25).
• Brain Health: Intermittent fasting increases a brain hormone called BDNF, and may aid the growth of new nerve cells (26, 27, 28). It may also protect against Alzheimer’s disease (29).

• Anti-aging: Intermittent fasting can extend lifespan in rats. Studies showed that fasted rats live as much as 36-83% longer (30, 31).

Keep in mind that the research is still in its early stages. Many of the studies were small, short in duration or conducted in animals. Many questions have yet to be answered in higher quality human studies (32).
More evidence-based details here: 10 Benefits of Intermittent Fasting.

Bottom Line: Intermittent fasting can have many benefits for your body and brain. It can cause weight loss, and may protect against type 2 diabetes, heart disease and cancer. It may also help you live longer.

Intermittent Fasting Makes Your Healthy Lifestyle Simple

Eating healthy is simple, but it can be incredibly hard to stick to.
One of the main obstacles is all the work required to plan for and cook healthy meals.
If you do intermittent fasting, this gets easier because you don’t need to plan, cook or clean up after as many meals as before.
Intermittent fasting is actually very popular among the “life hacking” crowd because it improves your health while simplifying your life at the same time.

Bottom Line: One of the major benefits of intermittent fasting is that it makes healthy eating simpler. There are fewer meals that you need to prepare, cook and clean up after.

Some People Should be Careful With Intermittent Fasting (or Avoid it Altogether)

Intermittent fasting is certainly not for everyone.
If you are underweight, or have a history of eating disorders, then you should not do intermittent fasting without consulting with a health professional first.
In these cases, it can be downright harmful.

Should Women Fast?

There is some evidence that intermittent fasting may not be as beneficial for women, as it is for men.
For example, one study showed that it improved insulin sensitivity in men, but worsened blood sugar control in women (33).
Although there are no human studies on this, studies in rats have shown that intermittent fasting can make female rats emaciated, masculinized, infertile and cause them to miss cycles (34, 35).
There are plenty of anecdotal reports from women who became amenorrheic (their menstrual period stopped) when they started doing IF, then went back to normal when they stopped doing it.
For these reasons, women should definitely be careful with intermittent fasting. Ease into it, and if you have any problems like amenorrhea then stop doing it immediately.
If you have problems with fertility and/or are trying to conceive, then consider holding off on intermittent fasting for now. Intermittent fasting is probably a bad idea when pregnant or breastfeeding.

Bottom Line: People who are underweight or have a history of eating disorders should not fast. There is also some evidence that intermittent fasting may be harmful for some women.

Safety and Side Effects

Hunger is the main side effect of intermittent fasting.
You may also feel weak and that your brain isn’t performing as well as you’re used to.
This may only be temporary, as it can take some time for your body to adapt to the new meal schedule.
If you have a medical condition, then you should consult with your doctor before trying intermittent fasting.
This is particularly important if you:

• Have diabetes.
• Have problems with blood sugar regulation.
• Have low blood pressure.
• Take medications.
• Are underweight.
• Have a history of eating disorders.
• Are a female who is trying to conceive.
• Are a female with a history of amenorrhea.
• Are pregnant or breastfeeding.

Bottom Line: The most common side effect of intermittent fasting is hunger. People with certain medical conditions should not fast without consulting with a doctor first.

Frequently Asked Questions About Intermittent Fasting

Here are answers to the most common questions about intermittent fasting.
1. Can I drink liquids during the fast?
Yes. Water, coffee, tea and other non-caloric beverages are fine. Do not add sugar to your coffee. Small amounts of milk or cream may be okay. Drinking coffee will make you intermittent fasting much easier because Coffee can blunt hunger . However not everyone can drink coffee on empty stomach, read this A Reason NOT to Drink Coffee on an Empty Stomach

2. Isn’t it unhealthy to skip breakfast?
No. The problem is that most stereotypical breakfast skippers have unhealthy lifestyles. If you make sure to eat healthy food for the rest of the day then it is fine.
3. Can I take supplements while fasting?
Yes. However, keep in mind that some supplements (like fat-soluble vitamins) may work better when taken with meals.
4. Can I work out while fasted?
Yes, fasted workouts are fine. Some people recommend taking branched-chain amino acids (BCAAs) before a fasted workout.
5. Will fasting cause muscle loss?
All weight loss methods can cause muscle loss, that is why it is important to lift weights and keep protein intake high. One study shows that intermittent fasting causes less muscle loss than regular calorie restriction (16).
6. Will fasting slow down my metabolism?
No. Studies show that short-term fasts actually boost metabolism (14, 15). However, longer fasts (3 days or more) can suppress metabolism (36).
7. Should kids fast?
That’s probably a bad idea.