Eat dinner earlier, not later. A small study looked at the time dinner was eaten and the interval to bedtime. They found that eating a late dinner affects the metabolism negatively: blood sugar levels were higher, and the amount of ingested fat burned was lower, when compared to those eating an earlier dinner. Dinner was the same foods, just eaten at 2 different times.
The 20 young, healthy participants ate dinner at either 6 pm or 10 pm, and bedtime was at 11 pm. According to the results of the study, eating a late dinner alters metabolic markers during sleep in a way that could lead to obesity or diabetes. "The peak glucose level after late dinner was about 18% higher, and the amount of fat burned overnight decreased by about 10% compared to eating an earlier dinner."
This adds to evidence suggesting that the time meals are eaten can influence the development of obesity and metabolic syndrome. Sleep lowers the metabolic rate. Other studies have also found that eating earlier is better than later: for example, weight loss is greater in those eating the main meal of the day earlier rather than later.
The weird thing was, these effects were found even though the early dinner group was given a 200 calorie snack at 10 pm. So it's not like they had zero calories after their 6 pm dinner. (The late dinner group ate the same snack at 6 pm.) Based on these findings, I wonder how much better the metabolic markers would have been if zero calories were eaten after the 6 pm dinner?
From Science Daily: People who eat a late dinner may gain weight
Eating a late dinner may contribute to weight gain and high blood sugar, according to a small study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.
Over 2.1 billion adults are estimated to have overweight or obesity which make health complications like diabetes and high blood pressure more likely. Some studies suggest that consuming calories later in the day is associated with obesity and metabolic syndrome.
... "If the metabolic effects we observed with a single meal keep occurring chronically, then late eating could lead to consequences such as diabetes or obesity."
The researchers studied 20 healthy volunteers (10 men and 10 women) to see how they metabolized dinner eaten at 10 p.m. compared to 6 p.m. The volunteers all went to bed at 11 p.m. The researchers found that blood sugar levels were higher, and the amount of ingested fat burned was lower with the later dinner, even when the same meal was provided at the two different times.
"On average, the peak glucose level after late dinner was about 18 percent higher, and the amount of fat burned overnight decreased by about 10 percent compared to eating an earlier dinner. The effects we have seen in healthy volunteers might be more pronounced in people with obesity or diabetes, who already have a compromised metabolism," said the study's first author Chenjuan Gu, M.D., Ph.D., of the Johns Hopkins University.
This is not the first study to show effects of late eating, but it is one of the most detailed. Participants wore activity trackers, had blood sampling every hour while staying in a lab, underwent sleep studies and body fat scans, and ate food that contained non-radioactive labels so that the rate of fat burning (oxidation) could be determined.