Intermittent Fasting: What It Is and Its Benefits

When it comes to eating, there is no judgment. Every human being has their own circumstances and metabolism, and no routine or practice should be denigrated.  

Precisely, one of the practices that has gained the most prominence lately is intermittent fasting. But the truth is that it is nothing new; on the contrary, many cultures and religions have been practicing it since antiquity, as a form of purification or spiritual preparation.

The return to this practice arises from the need to find new formulas to feel better, or to lose weight. However, what is intermittent fasting? What are its benefits? Is it recommended for everyone? we explain all these doubts below.

What is intermittent fasting?

Intermittent fasting is an eating pattern that alternates, as its name suggests, periods of fasting with periods of eating. It is not a diet in the usual sense.

There are two main categories of fasting:

1. Weekly intermittent fasting (e.g., 5 days of normal eating and 2 days of very calorie-restricted meals).

2. Time-restricted eating (e.g., eating only within 8, 6, or 4-hour windows per day).

What are its benefits?

Among the most notable are:

• It prolongs life, but this has some nuances. It only works when there is caloric restriction. Because what promotes that longevity is consuming fewer calories than you expend, not intermittent fasting itself. Furthermore, that caloric restriction occurs with or without fasting. 

• It promotes autophagy, the cellular cleaning system responsible for eliminating waste and preventing inflammation. And, again, it only works if caloric restriction is met.

• It improves mitochondrial biogenesis. This is also true, but again, only if there is a caloric deficit. Increasing the quantity and quality of mitochondria is key to slowing down cellular aging. A key improvement for metabolic diseases and achieving greater longevity. (A note: physical exercise will always be much better for this than fasting).

Is fasting “better” than a diet?

No, as we have commented above, studies show that intermittent fasting is neither “better” nor “worse” than following a traditional balanced diet when it comes to losing fat, regulating cholesterol or blood pressure levels, or improving insulin response.

What is truly effective is following a healthy diet, based mainly on protein, fruits, vegetables, and fiber. And, if you are looking to improve metabolic health or lose weight, follow a caloric restriction.

When does it make sense to practice it?

When these circumstances occur:

In people who:

• Find it comfortable and it fits their lifestyle.

• Do not have eating disorders.

• Do not present risks of malnutrition or muscle mass loss.

• It can also be beneficial for people with: irritable bowel syndrome, bacterial overgrowth, or chronic constipation (as it promotes the functioning of the migrating motor complex, which cleans the intestine between meals).

Or in situations where:

• A balanced intake of nutrients is guaranteed.

• Eating is done with real food.

• Foods very rich in sugars, saturated fats, or refined flours are avoided.

• It is complemented by sports practice.

And when does it not make sense or is not recommended?

In people:

• Over 70 years old, because it implies a risk of muscle loss.

• In children under 12 years old.

• In pregnant or breastfeeding women.

• In people with a very low BMI.

• In people who suffer or have previously suffered from EDs (eating disorders).

If you are interested in expanding your knowledge on this topic, we leave you this chapter of “Tus Amigas Las Hormonas” where Dr. Medical-Scientist Isabel Viña explains it clearly.