Circadian Cycle – Know More About It!

Circadian Cycle – Know More About It!


By Dr. Bhavna Gandhi, Dietitian/Nutritionist

Circadian Rhythms are the daily cycle of mental, behavioral, and physical changes. These mainly react to the light and dark environment of organisms such as humans, animals, plants, and microbes. Being wide-awake during the day and sleeping at night is one of the examples. The study of Circadian Rhythms is known as Chronobiology.

Is the Biological Clock and Circadian Cycle Same?

Circadian Rhythms and their timings are produced and regulated by the Biological Clock.

Innate timing device of an organism is known as Biological Clock. Specific molecules or proteins which interact in cells throughout the body compose the biological Clock. These innate clocks are also identified in organisms other than humans such as mice, fruit flies, and other microbes. These clocks are different from Circadian Rhythm or Cycle but they are related.

How is the Circadian Cycle Produced?

Internal factors of the body along with environmental signals help in producing Circadian Rhythm. Daylight is the chief cue that influences the Circadian Rhythm. This daylight can turn on and off the genes responsible for controlling the molecular structure of Biological Clocks.

Changes in the light and dark cycle can slow down, speed up, or reset the innate body clocks. Circadian Rhythm can affect one’s body temperature, eating habits, sleep-wake cycle, digestion, hormone release, and other significant bodily functions.

Slow and fast biological clocks can disrupt the Circadian Rhythm. This irregular and abnormal Circadian Rhythm can lead to the number of chronic health problems such as obesity, depression, seasonal affective disorder, sleep disorder, diabetes, and bipolar disorder.

Diet and Circadian Rhythm

Research and studies show that maintaining a healthy and balanced diet solely is not responsible but the timing of eating food has the same importance. An individual’s body functions optimally when its functions are aligned with Circadian Rhythm. Eating meals late and snacking at midnight are some of the examples which can disrupt the Circadian rhythm and thus, can lead to metabolic problems and unhealthy weight gain.

Studies suggest that consuming a high quantity of food earlier during the day is better for one’s health. Blood sugar control is worst in the evening and best in the morning. Hence, one digests food more efficiently in the morning.

During the night, our brain releases melatonin, which prepares an individual to sleep. Eating and snacking late-night sends a misleading signal to the body clock. Eating late in the evening forced the organs to work during their dormant time which can escalate the risk of diseases.


Circadian Rhythm is a daily cycle that affects one’s mental, physical and behavioral processes. Any disruption in the Circadian Rhythm not only affect one’s sleep pattern but overall health. This disruption can cause various chronic problems.

Eating late in the day or mid-night snacking affects the Circadian rhythm and biological clock of an individual. It is important to align food consumption with the natural Circadian Rhythm for better health.