Intermittent Fasting

There is no doubt that reducing excess body fat affects tissue insulin sensitivity. For this purpose, in addition to following a diet with a negative calorie balance, we can also use various methods and tricks that will support us in the weight loss process.

First and foremost, a diet with a low glycemic load will have a wonderful impact on energy levels, satiety, and overall well-being. Thanks to it, it will be easier for us to achieve our goal and persevere in our resolution. We will not only take care of stable glycemia here. Benefits will also extend to other areas – we will take care of skin condition, hormonal balance, and slow down aging processes.

There is a certain tool that can also benefit many people—though not everyone—which I will discuss in a moment.

Intermittent fasting is a method of consuming food only within a specific eating window. There are many variations of fasting. A popular one is 16 hours of fasting and 8 hours of eating. There are even variations like 20/4 or others that involve fasting or eating only one meal a day, which accounts for 25% of the daily caloric intake.

We need to clarify something. Intermittent fasting is a tool! If we don’t maintain a negative calorie balance, unfortunately, we won’t be able to reduce body weight.

After about 12 hours of fasting, glycogen stores are depleted, and fatty acids are metabolized. We transition from glucose to ketones. It’s emphasized here that muscle mass remains well-preserved.

At this stage, we can pause for a moment. Since the positive effects of fasting begin as early as 12 hours after the last meal, aren’t we naturally in such a mode every day?

Let’s look at the numbers. By eating the last meal at 19:00 and having the first one at 9:00, we’re maintaining a 14-hour fasting window. Yes, that’s already intermittent fasting, even though it sounds like a regular day.

Let’s also remember that there will be a difference between a mild 12/12 fast compared to a 20/4 fast. I think this difference is noticeable.

The belief that during a specific eating window, one can eat “whatever they want.” It shouldn’t be like that. Let’s remember that the diet should be nutritious, anti-inflammatory, and health-promoting, and intermittent fasting should be seen as an additional tool.

For whom would intermittent fasting not be advisable?

  • for pregnant women
  • for breastfeeding women
  • for elderly individuals
  • for kids
  • for individuals with a predisposition to hypoglycemia (low blood sugar levels).

No extreme is good, and intermittent fasting is not a miraculous way to lose weight. It’s worth maintaining an overnight fast to give the digestive system time to rest and regenerate. It’s important to maintain daily rhythms, have 3-4 hour breaks between meals, and ensure meal regularity. Every patient is different and individual, but it can confidently be stated that a 3-4 meal pattern works best. For patients with hypoglycemia or gestational diabetes, we may sometimes increase the number of meals. A larger eating window increases the risk of hypoglycemia, so not everything that is trendy will always be suitable for us. Patients with type 1 diabetes (and type 2 as well) are prone to hypoglycemia. If we decide to try and assess our response, I wouldn’t recommend extremes like 16/8, 20/4 fasting, or fasting for the entire day. Before taking extreme steps in haste for quick weight loss, we should remember daily healthy habits, which will be the foundation and basis for our return to health.


Natalia Czubaj - Clinical Dietitian

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