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Brigham researchers probe how late eating could lead to weight gain

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In another blow to the midnight snack, a new study by researchers from Brigham and Women’s Hospital adds to the evidence that late eating leads to increased risk of obesity.

The study, published Tuesday in the journal Cell Metabolism, found that late-night eating was associated with people feeling more hungry, hormonal changes associated with being more hungry, people burning fewer calories, and molecular changes to fat tissue that pointed to increased fat growth.

The study supplements “accumulating evidence that late eating has detrimental effects on metabolism,” said Frank A. J. L. Scheer, director of the Medical Chronobiology Program in the Brigham’s Division of Sleep and Circadian Disorders.


“For people trying not to gain weight, the growing literature, including our data, suggests that eating later in the day is not a good idea,” said Scheer, the senior author of the study.

“In this study, we asked, ‘Does the time that we eat matter when everything else is kept consistent?’” lead author Nina Vujovic, a researcher in the program, said in a statement. “And we found that eating later makes a significant difference for our hunger levels, the way we burn calories after we eat, and the way we store fat.”

The study involved 16 people with a body mass index in the overweight or obese range. During two separate six-day stays in the lab, participants were fed the same three meals spaced over the course of a day. On one schedule, the meals began in the morning. On the other, the meals were shifted ahead by about four hours so the day’s meals began in the early afternoon.

Conditions in the lab were tightly controlled, including physical activity, posture, sleep, and light exposure. Participants were given a battery of tests, from surveys of how hungry they felt to, in some cases, biopsies of their fat tissue.


“Our results show that late eating consistently altered physiological functions and biological processes involved in regulation of energy intake, expenditure, and storage — each of these three in a direction favoring weight gain,” the study found.

Scheer said it was key to investigate the biological mechanisms “to know whether this is even supported by biology.”

“If we understand the mechanisms, we can design more targeted approaches,” he said.

One of the limitations of the study was that participants were only in the lab for six days at a time, he said.

Dr. Joseph Bass, a professor and chief of the Division of Endocrinology, Metabolism and Molecular Medicine at Northwestern University Feinberg School of Medicine, said the study’s findings were “a provocative, important result that encourages continued analysis.”

Martin Finucane can be reached at martin.finucane@globe.com.