Eating late at night linked to weight gain, diabetes and heart conditions

First experimental evidence now shows that late-night snacking can cause more than just weight gain. Eating meals late at night can increase the risk of developing diabetes and heart disease. This new study, conducted by the University of Pennsylvania School of Medicine, concluded that prolonged and delayed eating negatively affects fat metabolism and hormonal markers that are associated with cardiovascular conditions. These results were presented at SLEEP 2017, with researchers urging the public to be more aware of the hazards of proper timing when it comes to eating.

“We know from our sleep loss studies that when you’re sleep deprived, it negatively affects weight and metabolism in part due to late-night eating, but now these early findings, which control for sleep, give a more comprehensive picture of the benefits of eating earlier in the day,” lead author of the study Namni Goel, Ph.D., said on “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.”

For the purpose of the study, researchers observed nine healthy weight adults and had them undergo two conditions. Research subjects ate regularly during the daytime for eight weeks (specifically, three meals and two snacks between 8 a.m. and 7 p.m.) and then had a two-week “washout” period. This was to ensure that there was no carry over effect. Then, the same adults followed a delayed eating program for another eight weeks. This condition had them eat three meals and two snacks between noon and 11 p.m. Sleep was held constant, between 11 p.m. and 9 a.m.

Researchers measured the participants’ metabolic rates and blood levels at the beginning, after the first eating condition, after the washout period, and after the second eating condition. Results showed that when the participants ate later, they gained more weight — largely due to a retarded metabolic rate. Further analysis of the measurements revealed that delayed eating raised sugar and insulin levels, as reported on

Eating earlier in the day is hypothesized to stimulate hormonal changes that increase satiety levels. It was seen that the hormone ghrelin (which stimulates appetite) peaked earlier in the day among those who followed proper eating habits, while leptin (which prompts satiation) peaked later. This suggested to the researchers that daytime eaters received cues to eat earlier, which most likely helped them feel fuller for longer.

Dr. Goel’s team recognize that their study is a relatively small one, but say that their results are the first step in preventing overeating in the evening.

Midnight train to the morgue

Maybe being a night owl is not a good idea, considering you’re a human. Late-night eating negatively impacts your health. Diabetic, or pre-diabetic people, should especially be careful. According to, this metabolic condition can be prevented or managed with correct eating habits. This does not just mean what you eat, but when you eat. Nibbling on that cookie in the wee hours of the morning can:

  • Increase your risk for breast cancer — One study suggested that for every three extra hours of fasting at night, women had a 20 percent reduced risk of developing breast cancer and Type 2 diabetes.
  • Makes you have acid reflux — Here is the price you pay for late-time eating: heartburn. People normally go straight to bed after they eat, which forces acid from the stomach to “backwash” into the esophagus. Chronic heartburn can eventually lead to gastroesophageal reflux disease (GERD).
  • Cause you to be forgetful — Mice who were fed late at night when they should have been sleeping displayed impaired cognitive function. Researchers believe that a similar reaction can occur in humans.

Life sometimes forces us to stay up late at night, but that doesn’t mean our health should suffer for it. Practicing good eating habits as well as engaging in regular physical activity is enough to ensure good health.

Late-night snacking increases your risk of diabetes and heart conditions

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