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Eat less late at night to stay alert, say researchers

  • 3 Comments

Eating less food late at night may help curb problems with concentration and alertness that can accompany sleep deprivation, according to US study results.

The study involved 44 subjects, ages 21 to 50, who were unlimited access to food and drink during the day, followed by only four hours of sleep each night for three nights.

On the fourth night, 20 participants received continued access to food and drinks, while the 24 others were allowed only to consume water from 10pm until they went to sleep at 4am.

At 2am each night, all subjects completed a variety of tests to measure their working memory, cognitive skills, sleepiness, stress level and mood.

“Refraining from late-night calories helps prevent some of the decline those individuals may otherwise experience in neurobehavioral performance during sleep restriction”

David Dinges

During the fourth night, subjects who fasted performed better on reaction time and attention lapses than subjects who had eaten during those late-night hours.

In addition, subjects who ate showed significantly slower reaction times and more attention lapses on the fourth night of sleep restriction compared to the first three nights whereas study subjects who had fasted did not show this performance decline.

Results from the study will be presented at the SLEEP 2015 conference in Seattle.

“Adults consume approximately 500 additional calories during late-night hours when they are sleep restricted,” said the study’s senior author Dr David Dinges, from the University of Pennsylvania.

He added: “Our research found that refraining from late-night calories helps prevent some of the decline those individuals may otherwise experience in neurobehavioral performance during sleep restriction.”

In a related study, researchers from the same university found adults who were chronically sleep restricted may need to compensate for decreased morning resting metabolic rate by reducing caloric intake or increasing physical activity to prevent weight gain.

“Reducing the number of calories consumed can help prevent that weight gain and some of the health issues associated with obesity”

Namni Goel

In the study, 36 healthy adults slept for their usual amount for two nights. Next, they spent four hours in bed each night for five nights, followed by one night of 12 hours of recovery sleep. A control group of 11 subjects received 10 hours in bed each night for six nights.

In the experimental group, resting metabolic rate decreased after five nights of sleep restriction and returned to baseline levels after recovery sleep. No changes in resting metabolic rate were observed in control subjects.

Senior study author Namni Goel said: “Short sleep duration is a significant risk factor for weight gain and obesity, particularly in African Americans and men.

“This research suggests that reducing the number of calories consumed can help prevent that weight gain and some of the health issues associated with obesity,” she said.

  • 3 Comments

Readers' comments (3)

  • Laha78

    I think that all depends on what foods are consumed. I often don't have dinner until quite late at night and I never snack.
    Dinner always consists of healthy, home made meals, always consumed between 8pm and 10pm and I sleep extremely well each night.

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  • rubbish. many nurses on night duty tend to eat very little, if at all, which is also a problem for staying awake and concentration.

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  • when on night duty of a 12 hour shift, I used to breakfast at breakfast, cooked meal at 5 pm, start work at 8 pm, have 3 am Salad or simple meal and breakfast cereal before I went to bed. When I was on 7 days off, I just changed my simple meal to that of lunch. Along with the coffee (usually cold because I was busy working) I usually had my slump at 3- 4 am hence my break then. We need to listen to our body clocks. I still sleep (cat nap) for a short while on a long journey or on an afternoon. no I don't do shifts, but the Spanish have it right with siesta.

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