Meal Hours is an important factor for health and prevention of metabolic disorders

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Meal Hours is an important factor for
health and prevention of metabolic disorders

Lt. Gen. Mahmud Ahmad Akhtar
Former Surgeon General Army/DGMS (IS)
Prof. Emeritus (Medicine and Therapeutics)

Medical scientists have done lot of research about the best diet for optimal health and for prevention of diseases particularly for metabolic syndrome - a complex of obesity, glucose intolerance, diabetes mellitus, hypertension, hyperlipidemia and their complications and sequelae. There is general agreement to have diet of natural whole grains, vegetables/ fruits, legumes/ pulses (lentils, beans, peas) nuts, seeds, mono saturated/ polyunsaturated oils (plant based) low fat dairy products, fatty fish, chicken, low saturated fat, red meat, sugar, salt - without trans-fatty acids, avoiding processed/junk food. Diet should be 90% plant based - only 10% animal based consisting of fish/marine products, chicken/birds meat etc.

Lt. Gen. (R) Mahmud Ahmad Akhtar

There is also an old adage “Take breakfast like a king, lunch like a prince and dinner like a pauper.” i.e. main meal breakfast, lunch moderate, dinner a small meal. It is known since long that those individuals who eat during night suffer more from metabolic syndrome disorders. Recently, scientists have been debating about the timings of the meals. Studies have shown that it is not just what is eaten which is critical for good health and prevention of diseases, particularly non-communicable/ metabolic but also the timings of the meals.

A growing body of research has suggested that bodies function optimally when we align our eating patterns with our circadian rhythm, which regulates our physiological functions like sleep/ awake cycles, etc. Professor Satchin Panda of the Salk institute - an expert on circadian rhythm, writing in the book “the Circadian Code”, has argued that people improve their metabolic health when they eat their meals in a daily 8 to 10 hour window. Taking their first meal in the morning and their last meal in the evening. Many workers earlier described the limited hours of eating as medical fasting with no restriction on water intake. Mentioning its benefits, Dr. Panda has explained it on the basis of circadian rhythm calling it time-restricted feeding. It follows from the idea that human metabolism follows a daily rhythm with hormones, enzymes, with digestive system primed for food intake in the morning and afternoon. According to his studies, an average person eats over a 15 hour or longer period, taking meals, snacks, nibbling at night etc. In Pakistan, most of the people take late evening meals and many take sweets, ice creams, soda, chips etc. late in the night. The shops and restaurants are overcrowded late at night. According to Dr. Panda, this mode of eating conflicts with human biological rhythms. Since long it is known that the body has a biological clock in the hypothalamus that governs our sleep-wake cycle, in response to bright light exposure through the mechanism of melatonin hormone. A couple of decades ago, scientists discovered that there is not just one clock in the body but every organ has an internal clock that governs its daily cycle of activity.

Pancreas during the day increases its production of insulin and then slows it down at night. The gut has a clock that regulates the daily ebb and flow of enzymes, the absorption of nutrients and the removal of waste. Furthermore, the micro biome, the community of trillions of bacteria (friendly to body) in the intestines operate on a daily rhythm as well. These daily rhythms are so integrated that they are programmed in our DNA. Studies show that in every organ thousands of genes switch on and off roughly the same time every day. Our planet has been inhabited by human beings since hundreds and thousands years and while many things have changed there have always been one constant. Every single day the sun rises and at night it falls. Dr. Panda said we are designed to have a 24 hour rhythm in our physiology and metabolism. These rhythms exist because just like our brains need to go to sleep each night to reform, reset and rejuvenate. Every organ needs to have down time to repair and reset as well.


Dr. Courtney Peterson in the department of nutrition science at the University of Alabama at Birmingham said that most of the evidence in humans suggest that consuming most of the food earlier in the day is better for human beings. Dozens of studies have demonstrated that blood glucose control is better in the morning and worst in the evening. More calories are burnt in the morning and food digested more efficiently in the morning as well. At night, the lack of sun light prompts the brain to release melatonin – sleep inducer hormone. Eating late in the evening sends a conflicting signal to the clocks in the rest of the body that it is still day time, Dr. Peterson said.

Dr. Paolo Sassone-Corsi the Director of the center for epigenetics and metabolism at University of California Irvine said, “Eating at the wrong time of the day places similar strain on organs involved in digestion forcing them to work when they are programmed to be dormant which can increase the risk of disease.”

Dr. Sassone-Corsi recently published a paper on the interplay between nutrition, metabolism and circadian rhythm concluded, “Its well-known that by changing or disrupting the normal daily cycles, there is increase of many pathologies. Dr. Panda and his team carried out experiment on genetically identical mice of two groups. One had round-the-clock access to high sugar and high fat food. The other took the same food but in 8 hour daily windows. Both the groups consumed the same amount of calories. The mice that ate round the clock got fat and sick while the mice on time-restricted regime did not. They were protected from metabolic syndrome – obesity, diabetes mellitus hypertension, dyslipidemia, fatty liver etc.

A recent study in Israel found that overweight adults lost more weight and had greater improvements in blood glucose, insulin and cardiovascular risk factors when they ate a larger breakfast, modest lunch and small dinner compared to the opposite, thus supporting the age old conventional wisdom. A time of a day when you are not getting bright light exposure then the different clock systems become out of sync. She said, it is like one clock is in the time zone of Japan and the other in the Hawaii USA. It gives metabolism conflicting signals about whether to rev up or rev down. It is like disrupting the central clock by flying across multiple time zones or staying awake late at night. Fatigue, jet lag, and brain fog sets in. In conclusion, a large number of scientific studies show that not only the type and quantity of food but also the timing of meals is also important – a type of medical fasting.

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