Benefits of ‘fasting’
A longer nighttime period without eating may aid weight loss.
Americans’ 24/7 culture of work, entertainment and digital connectivity now also extends to our eating patterns, according to new research. And that erratic, round-the-clock pattern has probably contributed to an epidemic of obesity and Type 2 diabetes.
But the pattern can be changed, and restoration of a longer nighttime “fast” shows promise as a means to lower weight and improve health, according to the research.
In a study that detailed the consumption patterns of more than 150 non-dieting people in and around San Diego for three weeks, researchers at the Salk Institute in La Jolla found that a majority of people eat for stretches of 15 hours or longer most days — and fast for fewer than nine hours a night.
Despite participants’ typical claim to consuming three meals a day, “a breakfast-lunch-dinner temporal pattern was largely absent,” the researchers wrote in an article published last week in the journal Cell Metabolism.
The 10% of eaters whose consumption “events” were most limited averaged 4.22 a day. The 10% who ate most frequently averaged 15.5 noshes per day. Fewer than 10% of participants went for more than 12 hours without eating.
In fact, just over 12% of participants’ daily average intake of 1,947 calories happened after 9 p.m., the researchers found.
And generally, that final 12% of the day’s calories was extra: Computing participants’ average caloric needs for maintenance of body weight, the researchers reckoned that, typically, all calories consumed by participants after 6:36 p.m. were over and above those needed to keep their collective weight stable.
The result appears to be a formula for steady weight gain and metabolic disturbance.
In mice being fed high-fat chow, the Salk researchers’ past studies have shown that among those allowed to eat anytime, obesity was rampant.
When researchers compressed the animals’ “feeding day” to eight or nine hours, those with the long fast stepped up their calorie consumption when they were allowed to eat.
Both groups of mice ended up taking in equal amounts of calories. But the fasting mice were less likely to be obese, and had lower levels of systemic inflammation, fatty liver disease, worrisome cholesterol and metabolic disturbance than those allowed to eat whenever they wanted.
The Salk researchers have suggested that a nightly fast of 10 to 12 hours might do much more than just limit the consumption of excess calories: Even without changing daily calorie intake, a lengthy nighttime fast appears to “reset” a circadian clock disturbed by 24/7 feeding and drive up the body’s ability to burn off extra calories.
While humans cannot have their chow taken away for half the day, the authors wrote, their “erratic daily rhythm of eating/fasting ... can be manipulated to obtain desirable health benefits.”