Sleep and Weight Gain: Why Nibbling Late at Night Could Be Part of the Problem

Light snacks are not just a thing for students. It is a guilt-laden habit that haunts people of all ages, especially those with weight.

So, what could contribute to the craving for cookies and fries after dinner? A new study suggests that this could be a sleep deprivation. Even when study participants were allowed to recover sleep over the weekend, cravings persisted. So, to avoid cravings induced by fatigue, we must sleep well, systematically, every night.

For the paper, published in February in the journal Current biologyresearchers used a deliciously rigorous study methodology to shed light on the health effects of not getting enough sleep and whether sleeping too little during the week could be offset by a senseless sleep . (Hat to Dr. Perry Wilson of Medscape, who reported it for the first time.)

They took 36 healthy volunteers and confined them to a laboratory for two weeks. First, they forced everyone to sleep nine hours a night for three nights. Then, they randomly badigned the study participants to one of three groups: a "sleep restriction" group allowed to sleep five hours a night; a control group that had the opportunity to sleep nine hours of luxury per night; and a "sleep recovery" group that only got five hours a night for five nights, followed by a weekend night and two more nights of sleep.

The researchers collected data on the amount of sleep, meal and insulin sensitivity monitoring of each participant, as well as on the amount of hormone that the body had to secrete to control blood sugar. (Low insulin sensitivity and insulin resistance are early signs of type 2 diabetes.) They also track participants' melatonin levels, another hormone that indicates biological day and night. of the biological clock.

They discovered an indictment of sleep deprivation – even after a restful sleep on weekends – and a possible explanation for the failure of some diets. While the three groups ate about the same amount of calories, the two sleep deprived groups had more at the end of the day, especially after dinner snacks. They also gained more weight during the study period compared to the control group. So, something about too little sleep stimulated a larger caloric intake later in the night, and this difference appeared on the scale.

Even more alarming, the sub-sleeping groups have seen their insulin sensitivity decrease – an effect that the control group has not seen – which means that their dietary habits and sleep disturbances disrupt their metabolism so encourage them to develop type 2 diabetes. Thus, the restful sleep of the weekend has failed to protect people from a decrease in insulin sensitivity.

This is only a short-term but well-designed study – and that's important because it adds to a growing body of evidence that chronic sleep deprivation is a risk factor for both obesity and diabetes. The study also recalls that sleep is often absent from the discussion of weight gain and obesity – and this should not be the case.

So, why not get enough sleep to encourage snacks and weight gain?

There are some possible explanations for why sleep deprived people gain weight more easily. We have to do with our metabolism. Before we get to the heart of the matter, let's quickly recap the three main ways our body metabolizes energy. We have the "basic metabolic rate" – or the way you spend energy when you rest. There is an energy expenditure related to physical activity. And there is the "diet-induced thermogenesis" – the amount of energy that your body uses to digest and absorb the calories in food. The latter represents about 10% of the total energy expenditure of the body.

The researchers looked at whether people were spending more energy preparing a meal later in the day and found that, regardless of physical activity, the body uses less energy to digest food late in the day. day. This means that we can convert more calories into fat – instead of burning – when we eat late at night.

Researchers have also repeatedly found that when we are tired – surprise, surprise – we eat more. In a meta-badysis of 11 studies, the authors showed that people consumed an additional 385 calories after a night of sleep deprivation. That's about the same amount as a serving of Haagen Dazs peanut butter ice cream a day.

A hormonal hypothesis may explain this trend: a lack of sleep hinders our hunger hormones, leptin and ghrelin, increasing our appetite. Sleep loss can also change the way our brains perceive food, as Brian Resnick of Vox explained. A lack of sleep seems to alter our food reward systems, making us more excited by a cupcake or fries than we would if we were well rested.

In addition to weight gain, it is also important to note that eating late at night is badociated with a higher risk of diabetes. Glucose tolerance determines how well your body can absorb sugar from your bloodstream into your tissues. And again, impaired glucose tolerance – or a decrease in insulin sensitivity – is a risk factor for type 2 diabetes.

Researchers have shown that the body has a much harder time managing blood sugar levels at night. And the reason is that the circadian system – the body's internal clock, which works in every cell – seems to regulate the way the body handles calories at different times of the day.

"What we've found is that if you eat an identical meal in the morning or in the evening, the glycemic response is relatively impaired in the evening compared to the morning," said Dr. Frank Scheer, neuroscientist at the University of Toronto. 39 Brigham Hospital and Women & # 39; s. at Harvard Medical School, said Vox previously. "In the evening, we can not handle the glucose load either."

Thus, not only do we poorly manage calories when we are tired, but we eat more often late at night, but we also tend to eat more calories.

Too many Americans are deprived of sleep

While the official recommendation of the American Academy of Sleep Medicine advocates at least seven hours per night for adults, one-third of Americans report sleeping less than that, on average.

So how can we sleep more? Start by checking your basic sleep hygiene: avoid caffeine after lunch, exercise regularly, but not too late in the day, and avoid alcohol or heavy meals before going to bed.

And, for the sake of God, take the mosquito nets out of your room. "If you can maintain the stability of your sleep, it means that you see the same light every day at the same time and that your body will detect its meaning," said the author. Sleepyhead: the neuroscience of a good nocturnal rest, Henry Nicholls, said Sean Illing to Vox. "And yes, most people do not understand how artificial light is disruptive to the brain. This confuses your brain to think that it is daylight and that it is really in bed. Now we know that this is the last thing we want to do – with too much eating and too little exercise – if we try to lose weight.