There's a strong link between sleep deprivation, obesity, and weight-gain, but we still don't fully understand why. A number of recent studies suggest that inadequate sleep can make us feel hungrier, make sweet foods more appealing, and even make us buy more food at the supermarket.
Sleeping less and eating more
A 2014 study published in the journal Phsyiology & Behavior found that insufficient sleep was associated with:
- Poor diet quality
- Excess body weight
- An increase in calorie consumption
Those who didn't get enough sleep were found to snack more during the day and eat more meals compared to healthy sleepers. Furthermore, the foods eaten by sleep-deprived individuals were more energy-rich.
Why eat more?
It's thought that we eat more calories when we don't get enough sleep due to:
- Changes in appetite hormones
- More time available for eating
- Psychological distress ("comfort eating")
- An increased sensitivity to food reward
- Higher energy requirements due to extended wakefulness
Although it has been suggested that just five days of insufficient sleep can increase energy expenditure by 5 percent, this can still lead to weight gain since sleep-deprived eaters have been found to** consume 42 percent more calories** in the form of additional carbohydrates, protein and fiber eaten after dinner.
It would appear that sleep deprivation makes sweet foods more appealing, too — at least in teenagers. Research involving 31 adolescents between 14 and 17 years of age found that when these teens were sleep deprived, sweet/dessert foods became more appealing — even though the participants did not report feeling hungrier than normal.
When we're sleep deprived, we're also far less likely to feel motivated to exercise — which can lead to additional weight gain.
Gender and ethnicity
The effects of sleep deprivation on body weight appear to vary according to gender and ethnicity, too. A large study involving 225 healthy adults between 22 and 50 years of age found that sleep-deprived African Americans gained more weight that Caucasians, and that sleep deprived men gained more weight than women.
What to do if you're gaining weight
One suggested fix that could make a difference is going to bed earlier, and subsequently, eating earlier.
American researchers studied 52 volunteers over the course of a week. Data showed that 56 percent were considered "normal" sleepers (they were half-way through a night of sleep before 5:30 AM). The rest were considered "late" sleepers (half-way through a night of sleep after 5:30 AM).
The late sleepers consumed more calories at dinner and consumed fewer fruit and vegetables. Furthermore, those who ate after 8 PM were more likely to be obese, regardless of when they went to bed or how long they slept.
Interestingly, researchers have also found that when men of normal weight went grocery shopping with a set budget after just one night of sleep deprivation, their basket contained 9 percent more calories and 18 percent more food by weight.
Of course, the best way to avoid weight-gain due to sleep deprivation is to get more sleep!
A small study involving 10 overweight individuals found that by getting more sleep by going to bed earlier and getting out of bed later, participants experienced a 62 percent reduction in their desire for sweet and salty foods.
It's important to note, however, that participants in this study were not insomniacs; in fact, insomnia sufferers were specifically excluded. Insomnia sufferers should avoid spending too much time in bed, as this can lead to increased anxiety and less sleep overall.
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