Research Claims That Midnight Eating May Increase Heart Disease, Diabetes Risk

Eating late at night can negatively effect fat metabolism and hormonal markers implicated in heart disease, diabetes and other health problems, a new study warns.

Compared to eating earlier in the day, prolonged delayed eating can increase weight, insulin and cholesterol levels, researchers said.

Namni Goel Associate Professor, University of Pennsylvania (UPenn)

“Eating later can promote a negative profile of weight, energy, and hormone markers – such as higher glucose and insulin, which are implicated in diabetes, and cholesterol and triglycerides, which are linked with cardiovascular problems and other health conditions.”

Researchers found that when participants ate later, compared to the daytime condition, weight increased. Respiratory quotient, i.e. the ratio of carbon dioxide produced by the body to oxygen consumed by the body that indicates which macronutrients are being metabolised, also rose during the delayed eating condition, indicating later eating led to metabolising fewer lipids and more carbs. The team found that a series of other measures reflecting negative metabolic profiles increased in the delayed condition, including insulin, fasting glucose, cholesterol, and triglyceride levels.

Researchers analysed nine healthy weight adults who underwent two conditions, one of daytime eating (i.e. three meals and two snacks between 8 am and 7 pm) for eight weeks and another of delayed eating (i.e. three meals and two snacks eating from noon to 11 pm) for eight weeks. There was a two-week washout period between conditions to make sure there was no carry over effect. The sleep period was held constant, between 11 pm to 9 am.

Researchers drew blood at the beginning, after the first eating condition, after the two-week washout, and after the second eating condition to get metabolic measures of the participants. This allowed the team to measure changes in weight, metabolism and energy used, and made sure the two week washout allowed all measures to return to baseline before the next condition. They also found that during daytime eating condition, the hormone ghrelin, which stimulates appetite, peaked earlier in the daytime, while leptin, which keeps you satiated, peaked later, suggesting that the participants received cues to eat earlier, and eating earlier likely helped them to stay satiated longer.

This suggests that eating earlier may help prevent overeating in the evening and at night. As sleep-wake cycles were constant, melatonin levels remained constant in both groups. “While lifestyle change is never easy, these findings suggest that eating earlier in the day may be worth the effort to help prevent these detrimental chronic health effects,” said Kelly Allison, associate professor at UPenn.



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