“If you’re constantly eating at a time of day when you’re not getting bright light exposure, then the different clock systems become out of sync,” she said. “It’s like one clock is in the time zone of Japan and the other is in the U.S. It gives your metabolism conflicting signals about whether to rev up or rev down.”
Most people know what happens when we disrupt the central clock in our brains by flying across multiple time zones or burning the midnight oil: Fatigue, jet lag and brain fog set in. Eating at the wrong time of day places similar strain on the organs involved in digestion, forcing them to work when they are programmed to be dormant, which can increase the risk of disease, said Paolo Sassone-Corsi, the director of the Center for Epigenetics and Metabolism at the University of California, Irvine.
“It’s well known that by changing or disrupting our normal daily cycles, you increase your risk of many pathologies,” said Dr. Sassone-Corsi, who recently published a paper on the interplay between nutrition, metabolism and circadian rhythms.
A classic example of this is shift workers, who account for about 20 percent of the country’s work force. Many frequently work overnight shifts, forcing them to eat and sleep at odd times. Nighttime shift work is linked to obesity, diabetes, some cancers and heart disease. While socioeconomic factors are likely to play a role, studies suggest that circadian disruption can directly lead to poor health.
In one experiment, scientists found that assigning healthy adults to delay their bedtimes and wake up later than normal for 10 days — throwing their circadian rhythms and their eating patterns out of sync — raised their blood pressure and impaired their insulin and blood sugar control. Another study found that forcing people to stay up late just a few nights in a row resulted in quick weight gain and reduced insulin sensitivity, changes linked to diabetes.
In 2012, Dr. Panda and his colleagues at the Salk Institute took genetically identical mice and split them into two groups. One had round-the-clock access to high-fat, high-sugar foods. The other ate the same foods but in an eight-hour daily window. Despite both groups consuming the same amount of calories, the mice that ate whenever they wanted got fat and sick while the mice on the time-restricted regimen did not: They were protected from obesity, fatty liver and metabolic disease.
Inspired by this research, Dr. Peterson conducted a tightly controlled experiment in a small group of prediabetic men. In one phase of the study, the subjects ate their meals in a 12-hour daily window for five weeks. In the other phase, they were fed the same meals in a six-hour window beginning each morning. The researchers had the subjects eat enough food to maintain their weight so they could assess whether the time-restricted regimen had any health benefits unrelated to weight loss.
Article source: https://www.nytimes.com/2018/07/24/well/when-we-eat-or-dont-eat-may-be-critical-for-health.html