Intermittent Fasting 101: How To Do It & What To Eat

Intermittent fasting can help encourage the body to detox, improve immunity, and also help improve mood and mental performance. This type of fasting consists of a planned system where you do not eat solid food for 16 to 32 hours straight, a few times a week and then you go back to normal eating, preferably choosing a diet that is low in sugar and fat.

To benefit from this type of fasting, the most common strategy to begin it is to not eat for 14 to 16 hours and only ingest liquids like water, and tea or coffee without sugar. However, this lifestyle is only recommended for healthy individuals and it requires the consent and support of a doctor, nurse, or health professional who knows about this type of fasting, to guarantee it is done correctly and that it is not harmful for your health.

Intermittent Fasting 101: How To Do It & What To Eat

How to start intermittent fasting

There are different ways of doing an intermittent fasting system, but in all of them, there are periods where you should do food restriction and periods where you are allowed to eat. 

Usually, if you've never done fasting before, a nutritionist may recommend you do intermittent fasting once a week, for a maximum of 16 hours, or start with a shorter fasting period and increase it gradually. For instance, you may start with a 12 hour fasting period and then increase the fasting period as you get used to it.

Before you start fasting, it is recommended that you have a low-carb meal. That way you won't feel so hungry during the fast. In the first four hours, the body uses the energy provided by this last meal and after that period, the body starts the process of autophagy, in which the energy source is provided by glucose-containing body cells, which boosts fat burning.

The 4 main types of intermittent fasting

The main types of intermittent fasting are: 

  • 16-hour fasting - this consists of not eating for 14 to 16 hours, including the sleep period, and then eating during the remaining 8 hours of the day. For example, having dinner at 6 pm and then only start eating again at 10 am the next day;
  • 24-hour fasting - this consists of a whole day and night fast, two to three times a week;
  • 36-hour fasting - this consists of not eating for one and a half days. For example, eating at 6 pm on one day and then not eating the whole of the next day and eat at 6 am on the following day. This type of fasting should only be done under doctor supervision and by those who are already used to fasting;
  • 5:2 diet - this consists of eating normally for 5 days and restricting food intake for 2 days by reducing calorie intake to around 500.

During the "no eating" period, you are allowed to have water and tea or coffee without sugar or sweeteners. It is common to feel very hungry in the first few days but then the body gets used to it. If you feel extremely hungry, just eat something light as it is not advisable to feel unwell if you are trying to adopt this habit.

What to eat after fasting 

After a fasting period you should only eat easy-to-digest, low glycemic foods and avoid fatty and sugary foods, in order to achieve better results. 

Recommended foods

When you break your fast, it is important to ingest low glycemic foods such as: 

  • Mushrooms;
  • Sweet potato;
  • Zucchini;
  • Quinoa;
  • Chicken breast;
  • Tin tuna or sardines;
  • Broccoli;
  • Spinach;
  • Tomato;
  • Cabbage;
  • Cauliflower;
  • Bone broth.

After fasting, fruits that can also be taken include apple, strawberries, raspberries, and blueberries. In addition, the longer you go without eating, the less the amount of food you should have, especially in the first meal.

Foods to avoid

Avoid deep-fried foods or food that is prepared with a lot of fat, such as French fries, deep-fried chicken, ice cream, cookies, or frozen food like lasagna. 

In order to lose weight when doing intermittent fasting, it is also important to exercise regularly. This can include going for a walk or going to the gym. However, do not do so on an empty stomach and seek the supervision of a physical activity practitioner.

Health benefits of intermittent fasting

The main benefits of intermittent fasting are that it:

  1. Regulates triglycerides and cholesterol: foods eaten before and after fasting are low in sugar and fat, and fasting encourages the elimination of excess fat that may be retained in the body, helping to regulate cholesterol levels;
  2. Speeds metabolism: contrary to popular belief that fasting slows down metabolism, this is only the case in longer fasting periods, such as those above 48 hours. In short, and controlled fasting periods, there is an increase in metabolic rate, which helps burn fat easier; 
  3. Regulates hormone production: fasting helps balance body hormones that are linked to weight control. For example, there is a decrease in insulin and an increase in noradrenaline and growth hormones;
  4. Fights flaccidity:  this diet does not decrease muscle mass like other diets that imply a big caloric reduction. Fasting also helps increase muscle mass due to the production of growth hormones;
  5. Removes dysfunctional cells in the body: the body becomes more active in removing dysfunctional substances and cells that can cause chronic diseases like cancer;
  6. It is anti-aging: because it stimulates the body to live longer, by preventing diseases and making organs and body tissues live longer.

Additionally, due to hormone regulation people who do intermittent fasting may also notice that their brain is more alert and active, and they have a general feeling of being well. 

Is intermittent fasting for everyone?

Although it has numerous health benefits, intermittent fasting is not recommended for people who have diseases like anemia, high blood pressure, low blood pressure or kidney disease, or those who require prescribed medicine on a daily basis.

It is also not recommended for:

  • People who have had or have anorexia or bulimia;
  • Diabetics;
  • Pregnant or breastfeeding women.

However, even those who are apparently healthy should have a check-up with a general practitioner to assess their overall health and carry out tests, such as blood sugar level tests, before starting this type of diet. 

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