How to do intermittent fasting? Know all the methods

In general, the practice of fasting involves  total abstention  from 8 to 24 hours. But there are several ways to perform intermittent fasting and they can be tested and adapted to meet the needs of each person – always remember to consult a nutritionist.

Blackout periods are generally pre-stipulated according to gender. For example, women can adopt a 14-hour fast, while men can extend it to 16 hours. But there are variations in resistance depending on body composition (more fat or more lean mass ), age or physical activity. Check out the main methods:


Method 16: 8 or Leangains

Attributed to physical trainer Martain Berkhan, the routine is better suited for practitioners of intense physical activities, aiming at muscle strengthening and fat reduction.

In this modality, the practitioner has 2 meals a day with an 8 or 10 hour space between each one. Thus, there is a 16-hour fast for men or 14 hours for women.

Generally, water, coffee, unsweetened tea and chewing gums are well accepted during the fasting period, as they help with hydration and cheat hunger, which can be a difficult factor to overcome in the first weeks.

It is a well accepted method among practitioners as it does not require many hours of fasting.

Considering an average of 8 hours of sleep, practitioners add 4 hours without eating before bed and 4 hours after waking up, completing 16 hours without food intake. The practitioners, on the other hand, add 2 hours before and after sleeping, adding up to 14 hours of fasting.

The main tip of the fans is to maintain consistent schedules, preventing the body from undergoing frequent hormonal changes, causing difficulty in adapting.

In this type of fasting, there is no limit on meals, as long as the period stipulated by the food window is respected. But food groups gain more weight and consist of intensifying protein intake and regulating fats and carbohydrates .

Read more: What is the Food Pyramid? Types (Brazilian), benefits and groups

On days when physical activity is practiced, it is indicated that the consumption of carbohydrates is greater than the intake of fats. On days without intense activity, it is recommended that the amount of good fats be greater than carbohydrates.

Proteins should be consumed in relatively high amounts every day. This means intensifying protein foods, but without exceeding the recommended maximum limits.

Method 6: 1

During 1 day of the week, 24 hours of complete fasting is performed. Among the famous fans, Coldplay singer Chris Martin follows the routine and fast with total food restriction, drinking only water.

Although some studies indicate that the adoption of a weekly fasting day can bring benefits to the body (cardiac, glycemic and neurological), others point out that weight loss can cause the loss of muscle mass. Therefore, it is necessary to monitor the body’s constitution (fat and lean mass ratio ).

Method 5: 2

Two days are chosen during the week to drastically reduce caloric intake (on average, 500 calories). During the days of restriction, the practitioner should prefer foods rich in water and fiber, which help in hydration and satiety.

For the rest of the days, the diet remains based on healthy and more natural choices. You can maintain a menu with greater restrictions for food groups or not, depending on the objectives of the fast. For example, opt for the complete elimination of sweets or just use refined brown sugar and stevia.

Among the studies published by the University of Manchester, they point out that this method can bring good results to brain functions and DNA repair. The indication is not to make too many severe restrictions. By consuming all foods in moderation, an understanding of satiety is created and you avoid feeling hungry.

Method 1: 1

It is known by other denominations, like “Fast of the alternative day” or “UpDayDownDay”. The standard consists of 1 day of normal food and 1 day of food reduction. Unlike complete fasting, days are based on fairly moderate energy intake.

On average, up to 500 calories are accepted on fasting days, with no banned foods. The practitioner can have fractional meals throughout the day (for example, lunch and dinner of 250 calories each) or eat only once.

Metabolic balance

The method indicates a fast of 5 hours between each meal. The pattern is easier to follow as it does not imply very long periods without eating.

Attributed to the German doctor Wolf Funfack, the diet aims to stabilize the rates of metabolism, avoiding hormonal changes and resulting in complete improvements (weight loss and health improvement).

Complete fasting or eat-stop-eat method

In this method created by Brad Pilon, it is stipulated 1 or 2 days a week to perform a complete 24-hour fast. When choosing 2 days, it is important that they are not consecutive. You can opt for fasting on Mondays and Fridays, for example. Thus, there is a space of 3 and 2 days between each abstention, consecutively.

Non-calorie drinks, such as water, coffee and unsweetened tea, are well accepted during restrictive days. The others tend to maintain a regular and balanced diet, with an indication for reinforcing fiber intake, opting for a varied and nutritious diet.

In general, there are no banned foods during the feeding period, not even refined sugar, sweets and pasta. The idea is to ingest moderately what one feels like.

Warrior fasting

It takes about 20 hours of fasting and the feeding phase lasts an average of 4 hours.

This type, initiated by Ori Hofmekler, seeks to alter the metabolic process, dividing the day into two food cycles. However, unlike the 16: 8 method, in which fasting comprises the period of sleep, in this case, feeding occurs before bedtime, fasting during the day.

The diet is especially indicated for practitioners of intense physical activities, such as  weight training , seeking to optimize muscle gains (hypertrophy or definition) and fat reduction.

Read more: Crossfit: what is it, benefits, for beginners, exercise, lose weight?

Supporters point out that night meals are meant to stimulate the parasympathetic nervous system, promoting relaxation, accelerating long-term metabolism and avoiding insulin spikes.

The practitioner must perform the training or physical activity at night and, up to 1 hour after the end, eat vegetables and fruits in small quantities. In up to 1 ½ hours, you should eat proteins of high biological value, that is, lean and that are well absorbed by the body.

After 30 minutes of protein intake, the practitioner should feed on a carbohydrate source, preferring whole foods with a high nutritional value. After another 2 hours, food is free, the last meal before starting the fasting cycle.

For example:

  1. A bodybuilding workout ends at 7 pm;
  2. At 8:30 pm a small portion of broccoli, carrot or apple is eaten;
  3. At 9:00 pm a small portion of grilled chicken, tuna or white cheese is eaten;
  4. At 11 pm a free meal is held, ending the food cycle.

36-hour fast

The method attributed to physical trainers John Romaniello and Dan Go is a “coma-stop-coma” unfolding.

The standard is more rigid than the others and is not suitable for all practitioners of intermittent fasting. The long period of abstaining from food can be harmful if carried out without progressive adaptation (starting with shorter periods of fasting and gradually increasing).

Food abstention is usually done on 1 day of the week and fluid intake without calories is accepted. On other days, food is free, giving priority to sources of fiber and vitamins .

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