Intermittent fasting: Is it right for you?

Methods, pros, and cons

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

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

METHODS

– 5:2 Method. This is a "more extreme" fast because for 1 to 2 days a week, you need to severely restrict your calories or completely abstain from food (500-800 calories maximum). This is commonly known as the "5:2 diet" where 5 represents the number of days you eat normally, and 2 represents the number of days you have to restrict calorie intake or reduce it by up to 50%.

– 16:8 Method. You fast for 16 hours and eat for the following 8 hours, with calorie restriction, of course. Typically, you fast until lunch, and then eat lunch, an afternoon snack, and dinner.

But when we talk about body composition, what does science say about this strategy?

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

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

And it is still a super controversial topic due to so many research limitations:

• Firstly, much research has been conducted 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 fasting hours, the number of fasting days, whether participants could eat at will or still had to maintain calorie restriction when not fasting, and whether they fasted completely on fasting days or could maintain a certain level of calories.
• They are not long-term, lasting a maximum of 12 months.

Conclusions

Therefore, for me it is not a strategy for everyone.

• Some studies have shown that intermittent fasting is an easy method to reduce calories if it becomes a habit, but others may develop a habit of overeating as a result of fasting, which would lead to an increase in body weight.
• Slowing down metabolism: Reducing energy intake too severely can lead the body to respond with physiological adaptations that can cause weight regain after losing weight during fasting. This means that people are very likely not to maintain their weight loss after extreme food restriction and, in fact, may gain even more weight. Obviously, that's not ideal. However, it is difficult to confirm this claim, because there has been no long-term study proving 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, to perform at your best.
• Possible nutritional deficiencies.
• Socially, it can be quite complicated.

What is certain is that there is limited evidence about its long-term effectiveness and the health problems it can bring. Now, in my opinion, it seems to me that it is a type of strategy that can be effective for some people for fat loss, without a doubt, with the help of a professional.
And I am a big fan of sustainable changes for long-term results, but I am not opposed to someone trying intermittent fasting.