Nutritionists have long debated what the best daily diet is for an ideal health condition. But now some experts believe that it is important not only to eat, but also when to eat
Nutritionists have long debated what the best daily diet is for an ideal health condition. But now some experts believe that it is important not only to eat, but also when to eat.
More and more research shows that when the diet is matched with the circadian clock, our body can operate at its best. Long-term disruption of this pattern, such as eating late or eating a snack in the middle of the night, can lead to weight gain and metabolic problems.
Based on this conclusion, Satchin Panda, a professor at the Salk Institute and an expert on human circadian rhythm research, proposed in the new book The Circadian Code that the daily eating period Controlling within 8-10 hours, that is, eating the first meal in the morning and eating the last meal in the evening helps to improve people's metabolic health.
This method is also known as the “Early Time-limited Feeding Method”, which stems from the human rhythm of daily rhythm, that is, the hormone levels, enzymes and digestive system in our body are more inclined to eat in the morning and afternoon. However, many people wake up from morning to eating until they go to bed. Dr. Panda found in his research that on average people eat for up to 15 hours or more a day, usually in the morning to get a cup of milk or coffee, drink a glass of wine before going to bed, eat a night snack, or A lot of other snacks such as potato chips and nuts.
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Professor Panda said that this diet is contrary to our biological rhythm.
Scientists have long discovered that there is a main biological clock in the human brain, which is located in the hypothalamus and can feedback the light to control the cycle of sleep and wakefulness. A few decades ago, researchers discovered that there were a lot of biological clocks in the human body, not just one. Each organ has an internal circadian clock that rules its daily cycle of activity.
During the day, the pancreas increases the secretion of insulin to control blood sugar levels, and at night the process slows down. The intestine also has a biological clock that manages the fluctuations in the amount of enzyme per day, the absorption of nutrients, and the discharge of waste. The flora of hundreds of millions of bacteria in our gut also operates on a daily rhythm. These daily rhythms are so ingrained that they are written into our genes: research shows that in every organ, thousands of genes work and rest at about the same time every day.
"We have lived on this planet for thousands of years. Although many things have changed, one thing is eternal, that is, the sun will rise and fall every day," Professor Panda said. "We are physiologically and metabolically set to have a 24-hour cycle. These rhythms exist because, just as our brain needs to be repaired, restarted, and rejuvenated every night, every organ needs to have Rest time to fix and restart.
Most signs in the human body suggest that eating early during the day is good for our health, says Courtney Peterson, an associate professor of nutrition science at the University of Alabama at Birmingham. Numerous studies have shown that blood sugar control is best in the morning and worst in the evening. At the same time, we burn calories and digest food more efficiently in the morning.
At night, the lack of light causes the brain to secrete melatonin, helping us to fall asleep. Eating too late at night will give instructions to other organs in the body that are contrary to their biological clock, Dr. Peterson said.
“If you continue to eat during the time when there is no light in the day, then the different clocks in your body will be disordered,” she said. "It's like a clock in Japan's time zone, and the rest in the US. This will give you a contradictory command of your metabolism, when will it speed up and when it will slow down."
When we fly through multiple time zones or drive a night train to disrupt the central clock in the brain, we feel tired, jet lag and brain chaos. Eating at inappropriate times of the day puts similar pressure on the organs involved in digestion, forcing them to continue working at rest, which may increase the risk of disease, UC Irvine's crown genetics and Paolo Sassone-Corsi, director of the metabolic center, said.
"As we all know, changing or disrupting the rhythm of a person's normal life increases the risk of developing multiple diseases," Dr. Sassone-Corsi said. She recently published a paper on the interaction between nutrition, metabolism, and biological rhythms.
A typical example is people working in shifts, which account for about 20% of the national workforce. Many people frequently go to night at night, which allows them to eat and sleep only at strange times. Night shift work is associated with obesity, diabetes, certain cancers and heart disease. Although socioeconomic factors are likely to play a role in it, studies have shown that day and night reversal can directly lead to health deterioration.
In one experiment, healthy adults were asked to delay their sleep for 10 days and start later than usual (which broke their biorhythm and diet patterns), and scientists found that this led to their blood pressure, insulin And blood sugar control ability decreased. Another study found that forcing people to stay for a few days in a row can lead to rapid weight gain and reduced insulin sensitivity, all of which are physical changes that lead to diabetes.
In 2012, Dr. Panda and his colleagues at the Salk Institute divided the genetically identical mice into two groups. One group can eat high-fat, high-sugar foods at any time, and the other group can only eat the same food in an 8-hour period. Although the total number of calories in the two groups of mice was the same, the group of mice that could eat at any time became fat and sick, but the mice that ate during the prescribed time did not.
Inspired by this research, Dr. Peterson conducted a tightly controlled variable experiment among a small group of pre-diabetic male patients. In one phase of the study, subjects ate for 12 consecutive hours for five consecutive weeks. In another phase, they ate within 6 hours of starting each morning and eating the same things. The researchers asked the subjects to eat enough to keep their weight constant so that the researchers could assess whether a diet that strictly controls the time would bring health benefits unrelated to weight loss.
This is true. During the period of tightly controlled feeding time, subjects showed lower insulin levels, lower levels of oxidative stress, less nighttime starvation, and greatly reduced blood pressure values. Their systolic blood pressure dropped by about 11 points and the diastolic blood pressure dropped by about 10 points.
“This is a very significant impact,” Dr. Peterson said. “This is exciting but also shocking.”
Although research suggests that eating earlier during the day is good for metabolic health, it does not mean that people can skip dinner. However, it may be wise to make your dinner relatively light. A group of researchers in Israel found that overweight adults can lose more weight when eating much less, eating moderately at lunch, and eating less at dinner than eating less at breakfast and eating more at dinner. And there is a big improvement in blood sugar, insulin and cardiovascular disease related factors. Dr. Peterson said that this confirms an old adage: breakfast is like a king, lunch is like a prince, and dinner is like a donkey.