How intermittent fasting affects health?

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Three main meals and snacks should be consumed daily for an adequate and balanced nutrition. Intermittent fasting which is a practice contrary to daily eating pattern recently arouses curiosity in the society with its potential effects. So, what is intermittent fasting? Can Ramadan fasting be an intermittent fasting practice? How can fasting and intermittent fasting support health?

What is Intermittent Fasting?

Intermittent fasting is defined as a phase in which consumption of energy containing food and drinks is restricted or not consumed during the day or on certain days of the week and after this period food and drink consumption continues normally as circular routine.

Intermittent Fasting Practices

Alternative Day Intermittent Fasting: It is a practice in which energy containing food and drinks are not consumed on certain days of the week and in the rest of the week there is no limitation for consumption of those foods and beverages

Regulated Intermittent Fasting: In this practice, individuals sustain their normal diet without any restriction for 5 days of the week. Energy intake is reduced down to 20-25% of their daily energy needs just for 2 days.

Time Limited Intermittent Fasting: In this practice, individuals completely limit energy intake at certain times of the day. Out of these periods, energy intake is not restricted

How can intermittent fasting affect our health?

It is suggested that intermittent fasting practices can improve health by providing weight loss and regulating metabolic indicators (such as blood glucose, insulin, cholesterol). It is determined that these effects can also be demonstrated by changing biological rhythm (circadian rhythm), bowel microbiota and sleep patterns.

Is fasting an intermittent fasting practice?

During the Ramadan, foods, drinks and water consumption is ceased between sahur and iftar (for about 12-18 hours depending on the length of the day). After iftar; food, drink and water consumption are ad libitum until sahur. Thus, fasting can be accepted as a limited intermittent fasting
practice, however in fasting water is not consumed unlike limited intermittent fasting.

Fasting and metabolic indicators

According to the results of 30 studies on how fasting effects fasting blood glucose, LDL cholesterol and HDL cholesterol levels, it was indicated that especially fasting blood glucose and blood LDL cholesterol levels were lower in both men and women after Ramadan.

In addition, it was found that fasting caused an increase in HDL cholesterol levels in women and a decrease in blood fat and total cholesterol levels in men. In addition to these positive impacts of fasting on body weight and metabolic indicators, it is stated that consuming food and drink in sahur during the month of Ramadan might cause unbalance of circadian rhythm. This suggests that fasting may not be effective on weight loss when compared to other intermittent fasting practices

What do scientific evidences say about intermittent fasting practices?

Intermittent fasting that gathers attention, but recent and comprehensive research results are needed to discuss health effects. Whereas weight loss with intermittent fasting shows progress in short term, it is also reported that it can cause hypoglycemia, headache and hypotension in short-term and may trigger nutrition deficiencies, may decrease basal metabolic rate and cause excessive nutrient intake (binge eating) in long-term. Keep in mind these recommendations while practicing intermittent fasting of which health effects will be better understood in the future with new and reliable investigations.

1. Although data suggesting that intermittent fasting practices may affect the body weight and metabolic indicators positively, but the evidence-based data is needed to answer the questions of which practice is the optimum or how long the fasting period should be or how many days in a week the fasting should be applied

2. There are hypothesis suggesting that intermittent fasting practices which limit the consumption of food and drink at night may improve health, but the results that support this hypothesis have been derived from animal studies and this hypothesis has not been tested on humans.

3. In order to evaluate the sustainability of intermittent fasting practices for healthy adults and how they affect the nutritional behaviors and metabolic indicators, further studies are needed for large scale and at least 1-year period

4. If you have an acute or chronic disease, consult your physician to start intermittent fasting.

5. When applying the intermittent fasting, be sure that you meet energy and nutrient daily requirement. If you notice symptoms such as lack of focus, fatigue, fainting, consult your physician.

6. In the fasting phase, avoid intensive exercise. Instead, you can prefer short walks, stretching and exercises at work during the day.

Sabri Ülker Foundation