Intermittent Fasting: The Benefits, Disadvantages, and Health Effects Explained by Expert Dietitian-Researcher Kirsten Berk

Being full of snacks around the clock doesn’t exactly help with your line. But is doing the opposite the solution if you want to lose weight? Bee intermittent fasting, in good Dutch intermittent, you leave your food for hours or days. Does this diet trend really help? Or is it unhealthy for your body? We asked dietitian-researcher Kirsten Berk from Erasmus MC.

Intermittent fasting can be done in several ways

There are different forms of intermittent fasting, says Berk. ‘That is why it is difficult to say anything in general about effectiveness.’ In some forms you fast every other day or eat (almost) nothing two days a week. You can eat normally for the rest of the days.

‘Another form is time-restricted eating,’ says Berk. Then you eat during part of the day (usually eight to ten hours a day), but you fast the rest of the time. ‘There are two versions of this. Bee early time-restricted eating you only eat in the morning and afternoon. Bee late time-restricted eating you only eat from noon onwards.’ The latter is especially popular: many people skip breakfast. But, Berk reveals, that is not the most promising variant of intermittent fasting
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How does such a temporary eating ban work?

There is the same idea behind all these solid shapes. Because you don’t eat anything for a while, your body first starts to burn your carbohydrate stores and then your fat stores. The result? You lose weight. This fat breakdown has an additional advantage: ketones are released. If you have a lot of these substances, it is a signal for extra maintenance for your cells, says Berk. This gives your cells a higher resistance to stress. In addition, you unconsciously eat less throughout the day. A combination of these factors will cause you to lose extra weight.

But wait a minute, isn’t that all possible with a typical diet in which you eat less, but spread it out throughout the day? Then you also fast. Unfortunately, research shows that such a continuous diet is difficult to maintain (and after a while of dieting, your body automatically goes into energy saving mode). The idea of ​​intermittent fasting is that by alternating fasting and eating normally, it is easier to maintain. Whether that is really the case remains to be seen. The few long studies that have been done have so far found no difference between intermittent and continuous fasting.

Skipping breakfast has no positive effect

In practice, the benefits of fasting don’t always seem to materialize. ‘The results of research on this subject are very variable,’ says Berk. In any case, science agrees: eating only after noon does not work better than a regular diet. So left scientists from University of California (USA, 2020) fifty overweight people fasted in the morning for twelve weeks and a comparable group ate all day long. At the end of that period, both groups had lost the same amount of weight.

In fact, skipping your morning meal can even be bad for your health. It seems to have an adverse effect on your metabolism. “That probably has to do with your biological clock,” Berk explains. Many processes and organs in your body follow a 24-hour rhythm. ‘In the morning, all those different clocks are synchronized by a combination of light signals and food,’ says Berk. If this does not coincide properly because you skip breakfast, the clocks can start to run unevenly. ‘And that is associated with chronic diseases.’ So what is a successful method of fasting?

Benefits of fasting late in the day

It is more promising to do the opposite: have a big breakfast and lunch, while eating your dinner early and light. In other words, trade your extensive dinner for a meager sandwich. And leave out all your evening snacks, because fasting starts at six o’clock.

Berk: ‘In the short term, people will lose more weight than with a continuous weight-loss diet and their metabolism also improves.’ This may make them less likely to develop diseases such as diabetes and cardiovascular disease. So bring on that tray full of sandwiches, eggs, yogurt and fruit in the morning.

Unfortunately, little is known about the long-term benefits of this form of intermittent fasting. For example, we are not yet sure whether your body will stay out of energy saving mode if you fast daily in the evening. This is because not much long-term research has been done yet. Berk hopes to change this with her own research that is now underway.

And the disadvantages?

Okay, so having a good breakfast and eating less and less during the day is beneficial for losing weight and your metabolism. But are there also disadvantages? ‘The most favorable form is to stop eating around five or six o’clock, but that can be very difficult socially,’ answers Berk. ‘Many social outings take place in the evening and are often accompanied by food.’ Then you may feel bad that, for example, you are the only one of your friends who does not order anything in a restaurant.

Despite this disadvantage, people seem to be able to continue fasting in the evening quite well. “We are currently conducting research into the long-term effects compared to continuous fasting,” says Berk. ‘And the first results look favourable. Also in terms of feasibility. In the first three months, eighty percent of the participants lasted almost every day.’ Before that, some people changed their daily schedule. For example, they postponed the hot meal to the afternoon or cooked in advance. So no problem at all, this change in eating pattern.

Conclusion

In short, there are many forms of intermittent fasting. The most favorable option at the moment seems to be early time-restricted eating, where you fast at the end of the afternoon and in the evening. This helps people lose weight and improve their health through their metabolism. But, Berk emphasizes, we do not yet know the long-term effects of this diet.

Psst. Don’t fast for too long, eh? A person cannot survive forever without food.

2023-12-12 16:18:22
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