Is it advisable to fast for 24 hours?

Is it advisable to fast for 24 hours

The 24-hour fast or one-day fast is one of the most attractive because it seems easy to assume, but how is it done? And most importantly: does it bring you benefits?

A day of fasting, 24 hours, is a slightly longer fast than what we practice daily at night or overnight fasting. The advantage is that 24 hours is enough time to make sure we enter ketosis , that is, to start burning fat as our main fuel.

To do this, two things are required: being aware and well informed that the 24-hour fast that is going to be carried out is a physiological maneuver , and understanding its mechanism to put it into action.

The easiest thing to do when fasting for 24 hours is to do without dinner one day and breakfast and lunch the next day . This allows us to enter ketosis, which we can easily verify, since one of the signs that we have started this type of metabolism will be the appearance of acetone in the urine, which is very easy to measure.

You can do this 24-hour fast once a week, every week , as a hygienic custom. So we would be doing a weekly intermittent fasting .


The first few times , imagine your 24-hour fast as a long-distance race : go slowly and watch your sensations.

Sometimes they are unpleasant sensations , such as nausea or headache, but most of the time they are temporary.

The ideal is to get up at dawn , wake up well and start daily cleaning, with water. Wash teeth, tongue and skin well.


As explained in detail in the video that you have at the beginning of this article, during the 24-hour fast we can drink water, diluted juices and some infusion or vegetable broth, as these liquids will not break the fast and will help us maintain it.

The infusions can be adapted if you have a health problem that you want to influence. But, in general, these are some examples of infusions that can be taken while fasting and that will help you in the process:

  • rosemary and anise grain
  • Licorice and anise grain
  • liquorice and mint
  • Thyme and anise in grain

These infusions are mainly aimed at stimulating blood pressure, which generally decreases during fasting. They are not indicated in hypertensive people.

An infusion alternative for hypertensive people would be aniseed, lemon balm and orange blossom.


The rest of the day you can do what you normally do, without missing:

  • A walk in the natural environment.
  • A bit of sun
  • A little exercise, with natural movements: walking, running, climbing, crawling, crawling, doing housework like cleaning the room or doing laundry…

The “breakfast”, the first meal after fasting , should be vegetable, with fresh fruit and vegetables, cereal or legumes, without heated fat or refined sugars.


The benefits of these “intermittent” fasts have been described in medicine since historical times, but in recent years many papers have been published on their effects. An example: those of the Nobel Prize winner Oshinori Ohsumi on autophagy, the mechanism that is activated by fasting and high-intensity exercise , and on its therapeutic applications. It has also been shown to be beneficial for the intestine that is inflamed or affected by an infection .

In fasting, the energy stored in fat cells is used for cell repair, resistance to stress and rejuvenation, so that day of fasting will have a revitalizing effect on us . This is a benefit of the 24-hour fast that we can all benefit from.

Fasting also facilitates weight loss and shedding body fat.

Fasting is also used for therapeutic purposes, for example:

  • In rheumatic diseases, improving the symptoms, or drug-resistant epilepsy .
  • It has the potential to delay brain aging, as it modifies nutrient sensory pathways in the brain and increases synaptic plasticity, neurogenesis, and neuroprotection.
  • During fasting there is a reduction in insulin and leptin levels, an increase in insulin sensitivity and resistance to diabetes, a reduction in resting heart rate and blood pressure, and an increase in heart rate variability ( as a result of increased parasympathetic tone).
  • There is also a decrease in inflammation, an increase in the resistance of the brain and heart to stress, and an improvement in functional outcome in models of stroke, myocardial infarction, and arteriosclerosis problems.
  • It also helps fight infections. In fact, the body almost always reacts by losing its appetite until the infection passes.
  • Finally, thanks to the work of Valter Longo , it has been seen that, in cases of tumors, fasting provides additive and possibly synergistic effects when combined with drugs used in standard cancer treatment.

Abbas Jahangir

I am a researcher and writer with a background in food and nutritional science. I am the founder of, our reputable online platform offering scientifically-backed articles on health, food, nutrition, kitchen tips, recipes, diet, and fitness. With a commitment to providing accurate and reliable information, we strive to empower our readers to make informed decisions about their health and lifestyle choices. Join us on's journey toward a healthier and happier lifestyle.

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