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Intermittent Fasting hours: How long to fast?

Intermittent Fasting hours: How long to fast?

We talk about Intermittent Fasting hours in this article.

Lately, you have gained a few more pounds, or rather several more pounds, especially in the arms, stomach and thigh.

Rest assured, you are not the only one (or the only one) in this case.

With the sun shining almost every day and the summer vacation looming on the horizon, you’ve decided to go on a diet to lose weight fast.

Never mind.

Even if you want to display a dream figure on the beaches, there is no question of endangering your health by depriving yourself of everything.

Either way, banning all the things you love to eat from your diet doesn’t mean you will lose weight quickly, on the contrary.

To lose weight effectively and sustainably, you must adopt the right strategies, and intermittent fasting is one of the most effective eating practices to regain your healthy weight while returning to a healthy and balanced diet.

What is intermittent fasting?

A fast is when you don’t eat anything for an extended period of time. Not sexy you think? Wait until you see the 3 possible types. Much like the Backstreet Boys, you can choose the one you like the most.

Alternative fasting

Alternative fasting consists of eating nothing for 24 hours, one to several times a week. For example, you eat as usual on Monday, you eat nothing on Tuesday, and you normally eat again on Wednesday.

Modified fast (5: 2 or 4: 3)

Modified fasting involves eating normally 4 or 5 days a week, then eating only 25% of your usual calories for the remaining days. For example, if you eat an average of 2000 calories per day, you should only eat 500 calories per day at least twice a week.

Fasting with time-limited eating (16: 8 or 20: 4)

The most “permissive” of the 3 types of fasting is time-limited fasting. It consists of eating nothing for a period ranging from 4 pm to 8 pm, then eating your usual meals during the time interval when it is “allowed”. For example, for a conventional 16: 8 fast, you would be allowed to eat only between 10 a.m. and 6 p.m. For a 20: 4 fast, you would be allowed to eat only in a 4 hour window (eg between 12 p.m. and 4 p.m.).

Why stop eating? I like it to eat me …

The intermittent fasting benefits 

  1. Decreased insulin levels
  2. Reduction of bad cholesterol levels in the blood
  3. Cleansing the body
  4. Weight loss (the main reason intermittent fasting is so popular)


WOW, does this work for real?

Excellent question, I like the fact that you question what the Internet is telling you.

Insulin level

First, what is insulin? It is a hormone produced after a meal by your pancreas and which allows the carbohydrates (elegant name given to the family of sugars) that you eat to enter your cells so that they can use them and produce energy. .

Insulin gets a bad rap because it is also “because” of it that the fat you eat is absorbed and stored in your adipose tissue. The logic of the anti-insulin and pro-fasting gurus is as follows: “if I don’t eat for a long time, my body doesn’t secrete insulin, I don’t store fat, and therefore I lose weight”!

Cute… but not true. What makes you gain weight isn’t bad insulin, it’s just eating more calories than you’re spending. So yes your insulin levels will be lower during the fast, but the insulin will come back after your meals. Conclusion: insulin is your friend.

Reduction of bad cholesterol levels in the blood

First, what is cholesterol? It’s a type of fat that can come from your diet or be synthesized by your liver. It is carried in your blood by proteins. When we say “bad” cholesterol or LDL, we are actually talking about the proteins that bring cholesterol to your cells, and when we talk about “good” cholesterol or HDL, we are talking about proteins that bring cholesterol back to your liver. is metabolized. The “bad” cholesterol is the one that promotes an accumulation of fat in your arteries and in the longer term, a poorer health of your heart.

Most studies done in connection with intermittent fasting report a decrease in blood levels of bad cholesterol. YES! In contrast, many of the studies that report it don’t compare intermittent fasting to normal calorie restriction, and those that do find no difference. In other words, it works, but no better than eating less.

Cleaning the body

A really nice nutritionist wrote a great article related to cleansing the body, or “detox”. Basically, your body is able to do the job without you needing to stop giving it food, or giving it $ 15 juice for 1 week.


The studies are clear: it works! Depriving your body of food for prolonged periods of time makes your left bones AND your right bones smaller. Many justify this result by arguing that it is due to a rearrangement of hormones and the fact that the bodies of those who do intermittent fasting are fueled by fat instead of sugar.

This is pretty much true. However, no difference was found for these markers when a review of all the studies that had been done compared intermittent fasting with normal calorie restriction.

So in simple words: Weight loss during intermittent fasting is due to eating less, period.


Enjoy a new relationship with food!

Intermittent Fasting: Why Is It Effective For Weight Loss?

As a reminder, intermittent fasting is a diet that alternates between period of food intake and period of fasting.

Generally, the faster can eat for 8 hours and fast for 16 hours (discover our Special Practical Guide for beginners), for example from 8:00 p.m. to 12:00 p.m. the next day or from 10:00 p.m. to 2:00 p.m. the next day.

So most of the time it’s about skipping breakfast.

However, you can skip dinner if your activities require you to eat a substantial breakfast in which case you can for example eat between 7:00 a.m. and 3:00 p.m. and then not eat anything until 7:00 a.m. the next morning.

It is possible to follow both options, the important thing is that you find the right rhythm that suits YOU.

During your free time window, you can eat anything, in reasonable amounts, of course, and with certain foods over others.

And for good reason, intermittent fasting is intended to reduce insulin secretion, which promotes weight loss.

Thus, even if there are no dietary restrictions during the feeding period, it is recommended to put a brake on carbohydrates (sugar and starches).

Putting the brakes on doesn’t mean you have to “ban” them, basically no food family is to be banned.

On the other hand, I recommend that you adapt your consumption according to your goal (do you want to lose weight?) And your lifestyle.

In addition, during the fasting period, water and unsweetened (not industrial) drinks are permitted. This is called water fasting.

So, in case of a little craving or a drop in shape, a glass of tea or coffee without sugar is always welcome.

This flexibility of intermittent fasting makes it easier to follow. People who practice intermittent fasting are therefore less likely to “crack” because they are not frustrated.

This is not the only benefit of intermittent fasting. Indeed, intermittent fasting has many health benefits:

  • Lets you lose weight: you can lose an average of 1 kilo of fat per week.
  • Helps to better manage appetite: thanks to intermittent fasting, you will learn to eat when your body tells you to and not when your mouth wants it.
  • Regulates satiety.
  • Helps maintain healthy weight.
  • Purifies the body and the mind. By being happier and better in your body, you will feel less need to snack.
  • Helps in the elimination of waste from the body.
  • Boosts our immune defenses.
  • Reduces the risk of developing cancer and type diabetes.
  • Reduces the risk of cardiovascular disease.
  • Helps prevent oxidative stress: preserves brain health, learning and memorization abilities.

For more efficiency, you can perfectly combine intermittent fasting with physical activity.

intermittent fasting hours
How long should you fast?

How long is intermittent fasting? 

When you reach your healthy weight, do you have to stop intermittent fasting and go back to your normal diet, but changing your eating habits (more fruits and vegetables, less carbohydrates)?

It should be noted that men have always had the habit of fasting.

In fact, food fasting has been practiced for millennia. The proof with Lent, Ramadan …

To go even further, our ancestors (during the Paleolithic period) also practiced intermittent fasting, by obligation of course.

Indeed, they only ate in the middle of the day, as the morning was devoted to foraging (hunting, fishing, gathering).

In summary, there is no deadline when you practice intermittent fasting.

Once you have reached your healthy weight, it is a tool that you adapt to your needs in order to maintain your weight without constraints.

Concretely, what should be intermittent fasting hours?

Many people have made intermittent fasting a way of life that keeps them slimmer and fitter in the long run.

Indeed, since it is a practice that is favorable to the good health of the body, why deny it?

So you can adopt this practice for as long as you want.

And the risks of deficiency you will tell me?

Let me reassure you right away, there aren’t any because you continue to eat every day, several times a day so you have every opportunity to have a diet that meets the needs of your body.

However, do not fall into either of these two traps …

Lock yourself into a too restrictive model

You can fast according to different “models”:

16/8 mode where you fast for 16:00 and you eat for 8 hours,
20/4 mode, the idea is the same except that you fast for 8:00 p.m. and you eat for 4 hours,
23/1 mode, in this case you only eat one good meal during the day

All of these options are equally valid.

However, just because you have found the formula that suits you best does not mean that you should lock yourself into this model and refuse any occasion or moment of conviviality to share a good meal with your family or friends.

You can perfectly “break” your routine every now and then when the opportunity arises. This is not what will “nullify” all the benefits of intermittent fasting.

Another trap …

Wanting to start too quickly

This does not have to be a trap or a mistake, because for many people, starting intermittent fasting is okay.

However, I prefer to “warn” you, especially if you are a little fragile (health problem, fatigue or chronic stress, relationship to food a little difficult, etc.).

Regardless of the duration of intermittent fasting, the important thing is to start fasting gradually to avoid possible side effects that are not always pleasant at first, such as dizziness, a headache, nausea or even a feeling of fatigue.

For example, start with a fast for a few hours, gradually shifting the time of your first meal or snack.

In addition, after the intermittent fasting duration, it is important that you maintain your eating habits and continue to engage in regular physical activities to keep yourself fit and healthy. In other words :

  • Eat more foods rich in fiber and more protein,
  • Avoid sweets and foods high in bad fats,
  • Avoid processed foods,
  • Get enough sleep and …
  • Listen to your body!

OK, but is intermittent fasting good or bad?

Again, great question, thanks for bringing me back to what really matters.

Many people have difficulty adopting better eating habits and eating a little less than what they spend every day. Result: it is difficult to lose weight. By setting fixed barriers (e.g. not eating between 6 p.m. and 12 p.m. the next day), we self-impose a structure that allows us to achieve the desired results, but by continuing to eat the same foods, just at different times .

So intermittent fasting is just a sexier way to eat fewer calories. It’s a bit like comparing an acai bowl to a smoothie: it’s really cool, but the only difference is you put decorations on top and post it on Instagram instead of drinking it. right in the container of your blender.

The risks

Wait a bit. Too much calorie restriction can be harmful for some people. Intermittent fasting is not recommended for …

Pregnant or breastfeeding women
People whose medication must be taken with food
Diabetics (close medical monitoring is required)
Athletes who train daily and / or multiple times a day

In addition, some side effects may occur:

  • Frequent and painful hunger pangs
  • Irritability
  • Bad breath
  • Anxiety and increased fixation on following the diet, which can lead to an eating disorder
  • Hypoglycemia
  • Dehydration
  • Difficulty concentrating and sleeping during the day
  • Decreased basal metabolism
  • Decreased physical activity
  • Infertility

For these reasons, close follow-up with a qualified healthcare professional is recommended.

I accept the risks; how to do?

This is the beauty of intermittent fasting: it’s relatively simple! You just have to eat what you usually eat, but with the difference of doing so within more strict time slots. For example, if you decide to go with the 16: 8 fast, you choose a time slot that suits your schedule and you impose 8 hours when you are allowed to eat (e.g. between 10 a.m. and 6 p.m.) . Note that you should try to eat roughly the same amount of food that you normally eat in 24 hours, but in 8 hours.

So intermittent fasting doesn’t promote better eating behaviors, but it does provide a slightly funkier way to achieve a calorie deficit and promote weight loss. Some even experience a spiritual process there. Anyway, if it fits your schedule and interests you, give it a try!

If you want advice that will allow you to achieve these same results, but less often hungry, stay tuned for my next articles.

Top 10 best seller books to master Intermittent Fasting

[amazon bestseller=”Intermittent Fasting” items=”10″ ]

References :

Golbidi, S., Daiber, A., Korac, B., Li, H., Essop, M. F., & Laher, I. (2017). Health Benefits of Fasting and Caloric Restriction. Current diabetes reports, 17(12), 123.

Johnstone, A. (2015). Fasting for weight loss: an effective strategy or latest dieting trend?. International Journal of Obesity, 39(5), 727.

Aksungar, F. B., Sarikaya, M., Coskun, A., Serteser, M., & Unsal, I. (2017). Comparison of intermittent fasting versus caloric restriction in obese subjects: A two year follow-up. The journal of nutrition, health & aging, 21(6), 681-685.

Mattson, M. P., Longo, V. D., & Harvie, M. (2017). Impact of intermittent fasting on health and disease processes. Ageing research reviews, 39, 46-58.

Klempel, M. C., Kroeger, C. M., Bhutani, S., Trepanowski, J. F., & Varady, K. A. (2012). Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women. Nutrition journal, 11(1), 98.

Muscle for life – Michael Matthews. How Insulin Really Works: It Causes Fat Storage…But Doesn’t Make You Fat. [EN LIGNE] (page consulted on April 4, 2018)

Radio-Canada – Découverte – Bouchra Ouatik. Jeûner pour améliorer votre santé. [EN LIGNE] (page consulted on April 4, 2018)

Stanford Medecine – Scope – Jennifer Huber. Intermittent fasting: Fad or science-based diet? [EN LIGNE] (page consulted on April 4, 2018)

Extenso. Le jeûne intermittent pour mieux contrôler le diabète [EN LIGNE] (page consulted on April 4, 2018)

The Washington Post. Despite the hype, intermittent fasting isn’t a magic weight loss cure. [EN LIGNE]–intermittent-fasting-isnt-a-magic-weight-loss-cure/2017/06/12/33dfc432-4b9e-11e7-9669-250d0b15f83b_story.html?utm_term=.1daf85e65e1d (page consulted on April 4, 2018)

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