Is intermittent fasting right for you?

Methods, pros and cons

Intermittent fasting is an eating strategy where you vary the periods of fasting and eating. And there are many ways to do it, from the times you fast to the meals you should eat.

This fashionable strategy claims a multitude of health benefits such as regulating blood glucose, increasing energy, increasing growth hormone (GH) production, reducing inflammation and lowering triglyceride (TG) levels and blood pressure, cancer, heart disease, stroke, eye disease, Alzheimer's and promoting longevity! But for now, all these studies are still in their early stages, mostly in mice, and so knowledge on these topics is limited, so there is plenty of room for scepticism.

METHODS

– Method 5:2. It is a "more extreme" fast because for 1-2 days per week, you need to severely restrict your calories or abstain from food altogether (500-800 calories maximum). This is commonly known as the "5:2 diet" in which 5 represents the number of days you eat normal, and 2 represents the number of days you have to restrict your calorie intake or cut back to 50%.

- Method 16:8. You fast for 16 hours and eat for the next 8 hours, with calorie restriction of course. Normally you fast until lunch, and eat at lunch, snack and dinner.

But when it comes to body composition, what does the science say about this strategy?

In a review of 980 subjects over 6 months, weight loss was found to be similar in both intermittent fasting and linear calorie restriction. Read
In another meta-analysis done over 12 weeks, there was no difference between linear calorie restriction to intermittent fasting in relation to body fat loss. Read
Along with these, many other studies conclude that there is no difference between linear calorie restriction and intermittent fasting for weight or fat loss. Read

In terms of weight/fat loss (apparently what makes these things catch on), the reason people who fast generally see results is because of the total amount of calories ingested, which always tends to be less than before. However, so far research has not found that fasting increases metabolism, or results in greater loss of body fat compared to other "diets".

And it is still a highly controversial subject because it has so many limitations in research:

First, a lot of research has been done on animals. Human studies are very small; most have fewer than 40 participants, and the largest has around 80 participants.
Studies vary according to the number of hours of fasting, the number of fasting days, whether or not participants could eat at will or still had to maintain a calorie restriction when not fasting, whether they fasted completely on fasting days or could maintain a certain level of calories.
They are not long-term, they have lasted a maximum of 12 months.

Conclusions

So for me it is not a strategy for everybody.

Some studies have shown that intermittent fasting is an easy method of reducing calories if it becomes a habit, but others may develop a habit of overeating as a result of fasting, resulting in an increase in body weight.
Slowing metabolism: Reducing energy intake too severely can lead the body to respond with physiological adaptations that can result in weight regain after weight loss during fasting. This means that it is very likely that people will not maintain their weight loss after extreme food restriction and, in fact, may gain even more weight. Obviously, this is not ideal. However, it is difficult to confirm this claim, because there have been no long-term studies that prove the sustainability of the diet.
You may experience headaches, fatigue, extreme hunger and low energy levels on fasting days. This can make it difficult to concentrate and perform to the best of your ability.
Possible nutritional deficiencies.
On a social level, it can be quite complicated.

What is true is that there is limited evidence about its long term effectiveness and the health problems it can bring, now, my opinion, it seems to me that it is a type of strategy that can be effective in some people for fat loss, certainly with the help of a professional.
I'm a big fan of sustainable changes for long-term results, but I'm not opposed to anyone trying intermittent fasting.