Is your body clock set to the right time?

Gerard Aragonès Bargalló
Researcher at the Department of Biochemistry and Biotechnology
gerard.aragones(ELIMINAR)@urv.cat

Despite the advances in scientific knowledge about nutrition and diet achieved over the past few decades, it is by no means clear that we are eating better. The relationships between health and diet are very complex, and other factors come into play that not only relate to what and how much we eat but also to when we eat.

Chrononutrition is a concept developed in 1986 by Dr Alain Delabos and research in the area has demonstrated that the time at which we consume food plays a key role in our health, particularly regarding our body weight. The general advice is to respect the body's biological rhythms and eat at the most favourable times in order to best assimilate the nutrients consumed

Biological rhythms are present in most animals, conditioning their periods of migration or hibernation, and also in plants, in which they regulate, for example, flowering and the shedding of foliage. In fact, many of our most basic biological processes, such as sleep, body temperature or blood pressure, exhibit rhythms. Most are circadian, meaning they repeat every twenty-four hours (related to the Earth's rotation), but we can also find others with different frequencies, such as weekly or monthly.

A person's circadian system is defined as the set of rhythmic oscillations of physiological variables within an approximate 24-hour period that work synchronously to anticipate and adapt to the cyclical conditions of each day. These rhythms are controlled by molecular "clocks" that are triggered by external factors such as light and mealtimes. Thus, a healthy circadian system associates day and light with intake and physical activity, while it associates night and darkness with fasting and rest.

Unfortunately, when these environmental cues are knocked out of sync (e.g. by shift work, irregular mealtimes, jet lag, insomnia, etc.), the circadian system stops working properly, which can directly influence body weight control and the development of overweight and obesity. Therefore, adapting meal times to take into account each individual's biological rhythm is crucial for keeping molecular clocks running correctly and thus preventing the onset and development of diseases related to being overweight and obesity.

In general, chrononutritionists recommend having the main meal of the day before 3 pm and the evening meal at least two hours before going to bed. It also warns of the risks, for example, of having dinner too late. Other recommendations include sleeping for seven to eight hours, spending at least twenty minutes on breakfast, and not being exposed to light from electronic devices at night.