The next time you stagger to the Waffle House late in the morning and order Texas eggs & melted cheese (1,040 calories), consider the findings of this new study: At around that time, the most basic operation of the human body strangles their calorie needs by about 10 percent compared with the rate at which they will burn calories in the afternoon or early evening.
Maybe you'd rather come back at dinner.
This pattern of calorie use does not vary significantly based on whether you are a servant who works at a funeral or a person aged 9 to 5 hours who stops by for breakfast after eight hours of closing his eyes, the researchers said. "Rest energy expenditure" of humans – the body's calorie use to carry out basic functions such as respiration, brain activity, and fluid circulation – following a cycle that can be predicted which increasingly days and decreases when night falls.
The new study, published this week in the journal Current Biology, offers further evidence that circadian rhythms dictate not only when we feel the urge to sleep but how complex mechanisms such as metabolism operate within a 24-hour period. This can help explain why people who make irregular sleep schedules, including swing workers, have higher obesity rates and are more likely to develop metabolic disorders such as type 2 diabetes.
And that shows that whether we hear it or not, our body clock always beats, putting us in our daily cycle with extraordinary precision.
At "zero hour" – roughly corresponds to somewhere between 4 and 5 in the morning – our core body temperature drops to its lowest point and the fuel use we idle reaches its nadir. From that point, initially quickly and then a little slower, "resting energy expenditure" body rises until late afternoon / evening. After reaching its peak at around 5pm, the number of calories we burn at rest subside for about 12 hours.
And then, just as surely as the day after night, we start again.
This new finding is a reminder that no matter how 24/7 our schedule is, our bodies are built for a slower and simpler world where humans move all day to search for food, eat at sunrise, and sleep when the sky is dark.
Today, our tastes and the availability of tempting foods throughout the night can encourage us to eat well after sunset. And our work may require us to sleep during the day and wait for a table, take care of patients or drive trucks all night. But our bodies are still attached to their ancient inflexible clocks.
The research findings are also accompanied by an implicit warning: When we ignore the biological rhythms that govern our bodies, we do so at risk.
Rest the energy expenditure account for most of the minimum calories we burn in a day. Just to spend one day eating, sleeping and breathing consumes 60 to 70 percent of our "rest energy expenditure." A serious mismatch when calories are consumed and the time when most of them are burned can encourage the body to make decisions – such as storing calories as fat – which is not necessarily healthy.
New studies add to the growing body of evidence showing that good 12-hour fasting, when in harmony with the darkness and nocturnal response of our bodies, may be a way to prevent or reverse obesity. In animal laboratories and more and more people, Salk Institute Satchin Panda researchers have demonstrated the impact of diet adherence to our circadian rhythms.
Others have shown the strength of time by showing how ready it can be disrupted.
In a 2014 study, 14 thin and healthy adults agreed to change their days upside down for six days. Give a diet that is sufficient to maintain their weight, the subject is quickly adapted by turning the thermostat down. Compared to the basic reading taken on their arrival (when they wake up during the day and sleep eight hours at night), subjects burn 52 fewer calories on the 2nd day of their swing-shift schedule, and 59 fewer calories on 3rd day of the schedule. .
Do it for a few days and you may feel a little tired. Do it for months, years or a lifetime, and the results can be stored too much fat and damaged metabolic processes.
"One that is taken is indeed for optimal health, including metabolic health, it's best for us to have a routine schedule of seven days a week – wake up and sleep at the same time and eat our food at the same time," said senior writer Jeanne F. Duffy, a neuroscientist and sleep specialist at Brigham & Women's Hospital in Boston.
"We have a strong watch within us and they are ready to handle certain events – eating and sleeping – at certain times of the day. So we want them to be optimally prepared for that. "
To get this finding, the researchers had to persuade seven people to spend three weeks in exile in a clockless windowless room, cellphone or Internet service. In the so-called "forced desynchronization protocol," the researchers extended the subject days by four hours. All get a minimum of eight hours in bed at the end of their long day, but then wake up and march through the "daytime" period of 18 hours before being allowed to sleep again.
At first, they seemed to be competing to follow this strange hour. But after three weeks of such discombobulation, the subject basically relies on their own internal clock to regulate the duration of their days and separate their days from the night.
The individual rhythms that each subject drops back don't show much variation: Without an alarm clock or other clues, they finally find their way back to the sleep and wake cycle that drifts around 24 hours, Duffy said.
At the end of the first week, the patterns in their resting hour energy expenditure became clear: In the time range from 23 to 24.5 hours, subjects who were cut off from day and night signals showed very similar patterns of resting energy use, and that followed daytime increases same day and night drop. These patterns remain unchanged until the end of the third week.
Along with that is a similar pattern of "macronutrient utilization." The subjects burn the most carbohydrates at the beginning of their waking period. The use of carbohydrates then decreases steadily, with a small jump in the middle of the night. The lowest fat burning in the morning, peaks in the afternoon, and decreases from there.
"We were impressed by the fact that these patterns are very similar between individuals," Duffy said. "It tells us that this is something real."
The amount of calories we burn – or store it as fat – might be influenced not only by our size, what we eat and the amount of exercise we get, Duffy said. Our meal times are also important.
When we sleep late at weekends, hopscotch crosses time zones, or works on a schedule that keeps us up all night then returns to the afternoon shift, "we disrupt our hours and make our metabolism inefficient, and in the long run, cause disease , "He said. "Staying on the same schedule is the best way to prevent it." —Los Angeles Times / TNS