The body has mechanisms to obtain energy from its reserves.
The 5:2 diet proposes to activate them in cycles of two days a week.
According to World Health Organization:
- Worldwide obesity has nearly tripled since 1975.
- In 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese.
- 39% of adults aged 18 years and over were overweight in 2016, and 13% were obese.
- Most of the world's population live in countries where overweight and obesity kills more people than underweight.
- 38 million children under the age of 5 were overweight or obese in 2019.
- Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016.
- Obesity is preventable.
The universe of diets is infinite. The issue of overweight is
so worrying that every year new diets emerge. And unfortunately, they are not
always appropriate or harmless.
The 5:2 diet emerged a few years ago in the United States.
There are numerous books that talk about it and even with different versions.
It consists of a couple of days of fasting - fasting being understood as a very
low energy diet - together with five days of "normal" food during
which a more or less balanced diet without specific restrictions is followed.
Lose Weight and Improve Your Health by Giving Your Food
Intake A Break
There are two ways to approach this type of fasting:
- Michael Mosley and Mimi Spencer (The Two-Day Diet, Ed. Urano) suggest that the two days of fasting be loosely interspersed throughout the week, consuming about 500 calories from unrefined plant foods.
- Michelle Harvie and Tony Howell (The two-day diet, Ed. Today's Topics) propose to make the two fasting days in a row and eating basically proteins.
The novelty of these diets is that they integrate fasting as a resource two days a week. They differ from the classic diets very low in energy based on food or protein preparations that are sometimes taken for weeks. With this system it seems that the weight goes down, but not only that.
Benefits Beyond Weight Loss
There are studies that show that this type of fasting has many advantages:
- Decreased plasma insulin
- Less lipids in the blood
- Less cholesterol
- Less inflammation markers
These diets thus put the debate on the beneficial effects of fasting on the table. Therefore, whether one wants to lose weight or not, well-managed fasting can have its advantages.
The keys to understanding the basis of the 5:2 diet are as follows:
1. Why Are Carbohydrates Limited?
Carbohydrates and their most basic unit, glucose, are the
body's main and fastest source of energy. When this type of nutrient is reduced
to the maximum, the body is forced to resort to fat - its main energy reserve -
which helps to lose weight.
2. Does the Body Have Glucose Stores?
Yes, in fact the muscle and liver store glucose reserves in the form of glycogen and the body metabolizes it before resorting to fats. But these are limited reserves. Expending glycogen is one of the reasons why water is lost when fasting.
3. Is It Necessary to Take Proteins During Fasting?
It depends. Proteins prevent a decrease in muscle mass, a
common effect of hypocaloric diets. In addition, proteins seem to be more
satiating and their metabolization requires more energy, which can be an
additional advantage if you want to lose weight.
4. Is It Possible to Reach Ketosis with This Diet?
Yes, especially if you do a lot of physical activity. When you do not take enough carbohydrates, when you metabolize body fat for energy, ketone bodies are produced. If it is a healthy person and this occurs for a short time there are hardly any negative effects.
5. Is It Better to Fast on Consecutive or Intercalated Days?
The most effective way for the body to activate the
appropriate metabolic pathways when food is scarce is to fast on two
consecutive days, but it is also usually harder. If the excess weight is not
very marked, it is preferable to intersperse them throughout the week.
6. And Wouldn't A Single Fasting Day Be Preferable?
One day of fasting can have its advantages but it can be
insufficient if you want to lose weight. The naturopathic medicine usually
advises, in fact, to fast one day a week. This is a good practice to maintain
weight, improve well-being or simply give the digestive system a break.
7. Can Everyone Follow This Diet?
Not everyone can follow it. People under 18 years of age,
pregnant women or people suffering from an illness should not follow this type
of diet. For obvious reasons, it is also not recommended for people who have
had an eating disorder.
8. Which Hormones Are Affected by Fasting?
Fasting markedly decreases insulin and leptin levels, which can be beneficial to the body. If insulin levels are too high because there is a strong or ineffective glucose intake, it favors the increase of fat deposits from glucose.
9. Does This Diet Work for Everyone?
No diet works 100% in all cases. It depends on a lot of
factors, such as age, weight, previous eating habits, physical activity,
genetics, etc. Therefore, it is not an infallible diet, but its effectiveness
has been proven to be high and it can be healthy.
10. What Foods Are Generally Recommended?
Outside the two fasting days, a varied and balanced diet is suggested, moderating foods rich in fats and refined sugars. On fasting days Harvie and Howell advocate eating mainly protein, while Mosley and Spencer advise vegetable juices and soups.
11. What Are the Disadvantages?
For some people eating so little two days a week can be very difficult. In people who are very sedentary and over 40 years of age, weight loss may be very small. If you opt for fasting days in a row, you will probably feel some fatigue... but it depends on each person.