Doctor explains fasting: what is known about intermittent eating and autofagy

Physician Pēteris Apinis published an article on 8 November in the Latvian newspaper Latvijas Avīze about fasting, or intermittent eating – a regimen in which a person fully abstains from calories during set periods. Responding to readers' questions, the author says fasting can be practised safely, but anyone wishing to start should discuss it with a family doctor. The topic is timely because the method has become very popular in recent years for weight control and health improvement.

What fasting is

The term comes from the English word “fasting”. In its modern sense it took shape in the late 20th century, when research on autophagy, insulin sensitivity and cell biology appeared. In Latvia it was popularised by the biohacking movement, whose followers use science, technology and data to optimise bodily function and extend healthy lifespan.

The most popular method is 16/8: during the 16-hour fast one may drink water, black coffee and tea without sugar or milk, while meals are eaten within an eight-hour window. In the 5/2 variant, a person eats normally five days a week and consumes 500–600 calories on two days. Another option is abstaining from food for a full day once or twice a week.

What research shows

According to Apinis, studies indicate that fasting reduces insulin resistance, lowers glucose and blood pressure, improves cholesterol readings and helps prevent or manage type 2 diabetes. The method rests on autophagy, the process by which cells clear out and recycle damaged components. Japanese scientist Yoshinori Ohsumi received the 2016 Nobel Prize in Medicine for discovering its mechanism.

Caution

Women are advised to choose gentler regimens, such as 14/10 or 12/12. Fasting may be unsuitable for pregnant women, people with eating disorders or certain chronic illnesses. The author admits that most studies cover a period from a few weeks to a year, while longevity data largely rely on research in mice and cell cultures.

The article also compares fasting with traditional Latvian seasonal eating and with religious fasts, including Christian, Islamic and Jewish traditions.