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For those of you who wonder if your weight increases when you have several sleepless nights, this article explains the relationship between sleep duration and diet, and whether you can lose weight through sleep.
Are sleep and diet related?
When you think about dieting, "dietary restrictions" and "exercise" usually come to mind, but "sleep" is also deeply related to dieting.
Getting quality sleep causes the body to secrete more hormones that suppress appetite and hormones that break down fat and develop muscles, making quality sleep essential for successful dieting.
Hormones related to sleep and diet
During sleep, various hormones related to dieting, as well as beauty and health, are secreted.
1: Growth hormone
The secretion of "growth hormone," which breaks down fat and develops muscles, is said to be most active in the first 90 minutes of sleep. Therefore, if the quality of the first 90 minutes of sleep is poor, the secretion of growth hormone decreases, making it easier to gain weight.
2: Cortisol
An increase in "cortisol," also known as the stress hormone, is said to lower the basal metabolic rate, which makes dieting less efficient. Cortisol secretion is said to be suppressed during sleep, so make sure to get enough quality sleep every day to become less prone to weight gain.
3: Leptin
When you eat, "leptin" secreted from fat cells stimulates the satiety center in the brain, suppressing appetite and making you feel full. In other words, an increase in leptin suppresses appetite, making it easier to lose weight.
Comparing well-rested days with sleepless days, it has been found that leptin secretion decreases after just two days of four hours of sleep.
4: Ghrelin
When the body lacks energy, a hormone called "ghrelin" is secreted from the stomach and stimulates the appetite center in the hypothalamus of the brain, leading to an increased appetite. Furthermore, an increase in ghrelin not only increases appetite more than necessary but is also said to make people prefer high-fat and high-calorie foods, such as rich ramen and cakes.
Comparing well-rested days with sleepless days, it has been found that ghrelin secretion increases after just two days of four hours of sleep.
5: Serotonin and Melatonin
The human body has an internal clock that switches between active during the day and resting at night. This internal clock is deeply related to "serotonin," which is secreted when exposed to bright light and awakens the brain, and "melatonin," which is continuously secreted at night and induces sleep.
Serotonin is secreted when exposed to strong light in the morning, and melatonin is secreted approximately 14 to 16 hours later. If these two rhythms are disrupted, for example, by waking up late and being exposed to light later, or by spending time in a room with blackout curtains drawn, sleep problems such as difficulty falling asleep or waking up can occur.
By resetting your internal clock in the morning, you will naturally feel sleepy at night and can establish a regular sleep rhythm.
Why lack of sleep and short sleep duration lead to weight gain
According to "Sleep and its deep relationship with lifestyle diseases | e-Health Net (Ministry of Health, Labour and Welfare)" by the Ministry of Health, Labour and Welfare, "Compared to healthy people who slept for a full 10 hours, it has been found that even just two days of sleep deprivation (4 hours of sleep) reduced the secretion of leptin, a hormone that suppresses appetite, and conversely increased the secretion of ghrelin, a hormone that enhances appetite, leading to increased hunger. Even a slight lack of sleep affects our eating behavior."
Another study found that people who slept for 5 hours had 16% less leptin and 15% more ghrelin compared to those who slept for 8 hours. Furthermore, an analysis of the average sleep duration and obesity risk in approximately 20,000 Japanese men revealed that men who slept less than 5 hours were more likely to be obese than those who slept 5 hours or more.
A research team at Columbia University in the U.S. surveyed 8,000 men and women aged 32 to 59 in 2005 and found that the obesity rate of people who slept 4 hours or less increased by 73% compared to those who slept an average of 7 to 9 hours.
As these various studies show, a state of sleep deprivation makes it easier to gain weight.
Sleep Diet Method for Weight Loss
Here's how to lose weight efficiently through sleep.
7–8 hours of sleep
According to "How is sleep duration related to obesity?" by the Japan Society for the Study of Obesity Prevention, "Data from the National Center for Health Statistics (NCHS) shows the percentage of obese individuals by sleep duration: 33.3% for less than 6 hours of sleep, 28.4% for 6 to less than 7 hours, 22% for 7 to 8 hours, and 26.3% for 9 hours or more."
It is clear that the obesity rate is lowest for those who sleep 7 to 8 hours, and a U-shaped correlation is observed, meaning the rate increases as sleep duration becomes shorter or longer.
To ensure adequate sleep, determine your bedtime by counting back from your wake-up time.
Use bedding that suits you
Choose a pillow that supports your neck, not your head, and a mattress that supports your lower back, not your upper back. In particular, if your pillow is not at a height that maintains the natural S-curve of your neck when you lie on your back, it can strain your neck and shoulders, preventing you from getting quality sleep.
Poor sleep can affect not only the risk of obesity but also your mental health and work performance, so it's important to use a pillow that suits you.
Sleep deeply for the first 90 minutes of sleep
As mentioned earlier, the secretion of "growth hormone," which helps break down fat and develop muscles, is said to be most active during the first 90 minutes of sleep. The quality of these first 90 minutes affects the quality of the rest of your sleep and is also related to leptin, which has an appetite-suppressing function. Therefore, how deeply you can sleep during the first 90 minutes is key.
Sleep and diet are related
Because there is a deep connection between sleep and diet-related hormones, you can either gain or lose weight depending on your sleep duration and quality. If you are conscious about dieting, why not focus not only on dietary restrictions and exercise but also on the quality of your sleep?
【References】
Ministry of Health, Labour and Welfare: "Sleep and its deep relationship with lifestyle diseases | e-Health Net (Ministry of Health, Labour and Welfare)"
Japan Society for the Study of Obesity Prevention: "How is sleep duration related to obesity?"
