They say that in extreme situations, desperate measures are taken. And that is precisely the first thing that may come to mind when we are in a hurry to lose weight. With miracle diets clearly losing popularity (about time!), the most common 'desperate' measure today is diving headfirst into the pool of intermittent fasting with the belief that it will be the quickest and easiest way to lose weight, without considering if it is really what suits us best.
A family doctor specializing in obesity and a member of SEEDO (Spanish Society for the Study of Obesity, creator of the Petratti Method and a nutritional coach ("besides being a mom, runner, and health educator"), Cristina Petratti clarifies everything we need to know about this eating pattern, starting from a fundamental premise. "Intermittent fasting is not a diet for weight loss. It is a temporary meal organization strategy that alternates periods of eating with periods of fasting. It is not about skipping dinner or eating without control when it's time, but about respecting the time windows or, in other words, the planning that corresponds to the option we have chosen."
What are the main alternatives? "The 12/12 (12 hours for food intake) would be the most suitable to start with, as it would be enough to have dinner at 8 p.m., for example, and breakfast at 8 a.m. From there, if the body tolerates it, you can progress to 14/10 (10 hours of intake), an intermediate level, or even to 16/8 (8 hours of intake), the advanced level." Additionally, there are 24 and 48-hour fasts, aimed at a metabolic reset and should only be carried out a couple of times a year.
What immediate impact does it have on our body? "Basically, it provides a rest for the body and a break for digestion." In the medium and long term, intermittent fasting has multiple benefits for metabolic health: "It helps control blood glucose levels and is a powerful tool to combat mild inflammation."
But, here comes the million-dollar question, does it help with weight loss? "Obviously, it promotes weight loss because, instead of counting calories, it helps us organize meals and reduces the time during which we can eat. It is also a great appetite regulator because by stabilizing insulin and ghrelin -which is the hunger hormone- it is easier for us to control those impulses that push us to snack all day."
In any case, she continues, "if the main goal is to lose weight or fat, a caloric deficit should be sought, which can only be achieved, in addition to with caloric restriction, with an increase in physical activity."
Like everything in life, doing intermittent fasting correctly has its rules, such as, for example, "during the waking hours, it is essential to take care of -especially in summer- hydration to avoid the loss of minerals." Therefore, it is recommended that "in addition to plenty of water, we consume infusions or bone broths."
And beware, because entering the intake window does not mean that we can indulge in whatever we crave or have in the pantry. "You cannot break the fast with pastries, cookies, cereals... In short, with simple carbohydrates. Why? Because this way we would suddenly raise blood insulin levels, which, after an initial energy boost, would cause a drop that would generate more anxiety to eat."
The ideal is to "opt for proteins (eggs, natural yogurt, or salmon); healthy fats (avocado, oily fish, nuts...) and complex carbohydrates (fruits or whole grains)."
Although it may seem like a strategy suitable for all audiences -in adulthood-, Dr. Petratti warns that "intermittent fasting is not recommended for pregnant women, those breastfeeding, or with a history of eating disorders."
At this point, this specialist concludes with a reflection as wise as it is realistic: "Intermittent fasting can be useful for specific periods, but it is hard to sustain over time because its practice implies a rigidity in schedules that, at times, is incompatible with daily life. Instead, I advocate for a combination of a healthy diet and exercise, focusing on strength training."