We check the time on the wall clock, on our wrist watch or perhaps on our mobile and decide our daily activities accordingly. Similarly our body has a built in neurobiological master clock smaller than a pinhead located in the brain and several peripheral oscillators throughout the body that synchronise perfectly to follow timing of key bodily functions and behaviours like sleeping, eating, waking etc.
Not only humans, but every living organism on earth - animals and plants – has internal clocks that evolved and made living beings diurnal or nocturnal. We follow a 24.5 hrs pattern known as the circadian rhythm based on sunlight and darkness. Sunlight being the strongest cue in this 24 hour pattern, there are duties that the body does during daytime and those devoted to night time. One of its night time duties is sleeping and deferring from eating.
Turning night into day:
Prior to the age of electricity the last meal was eaten by sunset. But now, wakefulness extends into night time changing our wake-sleep pattern. We sleep less at night and our meals are eaten way past sunset. Reduced sleep at night itself encourages night time eating. These go against the body’s circadian rhythm leading to obesity, diabetes, digestive issues, malignant cancers and heart problems.
Scientists say there is compelling evidence that mistimed eating affects our energy metabolism. Classic examples are those who regularly work nightshifts or travel time zones and suffer altered sleeping and eating patterns. They are twice more prone to obesity and cardiovascular diseases.
A time to eat:
Heavy meals or continuous snacking while watching TV late night is a sure call for bad digestion and obesity. Eating high fat meals regularly disrupts the biological clock, leading to obesity. A convincing study done in Spain showed that those dieters who ate their main meal (lunch) earlier in the day lost weight faster than those who ate it (same calories) later. Fasting throughout the night for 12 hours between dinner and breakfast is essential for the body’s systems to restore.
Similarly eating time, prescribed during Ramadan, of before sunrise and after sunset is healthy. But eating further big meals into the night beyond the evening Iftar simply undoes the goodness of fasting.
The time of eating is as important to the diabetic as how much and what. Researchers from Vanderbilt University found that insulin response follow the circadian 24 hours rhythm. Insulin sensitivity is reduced during night and eating at this time upsets glycemic control.
(The writer is a nutritionist)
