By Dr. Michael J. Breus
Clinical Psychologist; Board Certified Sleep Specialist
February 10, 2014
We all want our kids to learn healthy eating habits, to be active and to grow and live comfortably at a healthy weight. Yet for too many children, excess weight is a very real health concern. Too much junk food and too little physical activity are frequently-cited culprits in the problem. But what about sleep?
New research suggests that a moderate increase in sleep may prove effective in helping children eat less and lose weight. Researchers have found that extending sleep reduced calorie consumption, altered hormone levels associated with appetite, and contributed to weight loss.
Their results suggest that ensuring children get plenty of sleep on a regular basis may offer significant help in maintaining healthy weight and avoiding obesity.
The study included 37 children ranging in age from 8 to 11. Among the group, 27 percent of the children were obese. The three-week study began with all children adhering to their typical sleep schedule for one week. During the second week, the children were randomly divided into two groups. One group increased their sleep time, adding 1.5 hours to their nightly time in bed. The other group decreased their time in bed by the same amount. After a week, the groups switched sleep routines.
Throughout the study period, researchers tracked children's food intake, measured the levels of appetite-regulating hormones leptin and ghrelin, and also recorded weight. They found extending sleep was linked to lower calorie consumption, as well as hormonal changes and weight loss:
- During a week of moderately increased sleep, children consumed an average of 134 fewer calories per day than children whose sleep was decreased.
- Morning levels of the appetite-regulating hormone leptin were lower in children during the period of extended sleep. Leptin plays an important role in regulating metabolism and energy expenditure, signaling to the body that it has enough energy to function, thereby reducing appetite. Abnormal and high levels of the hormone can lead to leptin resistance, and the body becomes less equipped to use the hormone effectively to regulate appetite and metabolism.
- Children lost an average of 0.5 pounds during the week of increased sleep.
This study appears to be the first of its kind to investigate how adjusting sleep duration can affect calorie consumption in children. The results point to the strong influence sleep can have on eating behaviors, a connection we've seen established in a significant body of research involving adults.
Studies have shown insufficient sleep linked to an increased intake of hundreds of additional calories per day. Lack of sleep has also been shown to influence the types of foods we crave, leading to changes in brain chemistry that make unhealthful foods more tempting.
This latest study adds to a growing body of research that has established sleep as a critical factor in helping children establish and maintain a healthy weight. The importance of sleep in weight control can be seen even in very young children. What's more, childhood sleep habits appear to have an extended influence on appetite and weight as children age:
- Studies have shown that sleep patterns during the first months of life can influence risk for obesity down the road. Researchers at Harvard University found that babies and toddlers who slept fewer than 12 hours nightly had twice the risk of being obese at age 3. (The rates of obesity were highest among children who slept fewer than 12 hours and watched 2 or more hours of TV daily).
- Researchers in New Zealand conducted a study of the relationship between sleep and weight in children ages 3 to 7. They found that children who slept more at ages 3 to 5 had lower BMI at age 7 than children with shorter sleep routines during these younger years. Children who slept longer at ages 3 to 5 weighed less than shorter-sleeping counterparts, and were less likely to be overweight.
- A German study of more than 6,000 children ages 5-6 found that the prevalence of obesity was lowest for those children who slept more than 11 hours on a nightly basis. A study in China returned similar results, with preschool-age children who slept 11 or more hours nightly exhibiting lower rates of obesity than children who slept fewer than 11 hours.
- Sleeping fewer than eight hours nightly has been associated with a decline in eating habits among teenagers. Scientists at Case Western Reserve University found that teenagers who slept fewer than eight hours nightly during the school week consumed more calories on a daily basis than teens who slept at least eight hours. The teenagers who slept fewer than 8 hours also received more of their daily calorie intake from fats, and more of their overall calories from snacks.
This latest study provides further evidence that sleep can strongly influence eating habits and risks for weight gain in children, and that sleep can be an important therapeutic tool in helping children lose weight and keep it off. Rates of obesity among children have risen sharply over the past several decades, as the number of children and adolescents considered obese has more than doubled and even tripled.
Recent estimates indicate that these dramatically rising rates of obesity in children have leveled off, and in some cases begun to lower. Still, more than a third of children and adolescents are either overweight or obese, according to the Centers for Disease Control.
Obesity puts children at risk for many of the same health problems that adults face, including high blood pressure and cholesterol, increased risk of cardiovascular disease, as well as Type 2 diabetes. Breathing problems, including obstructive sleep apnea, are also more likely among children who are obese.
Weight problems that begin during childhood and adolescence often continue throughout adulthood: children who are obese are significantly more likely to be obese as adults, facing the range of serious health risks associated with excess weight.
To change these numbers, reduce these risks, and protect the long-term health of children, we must use all the tools in our arsenal to combat obesity in children and adolescents. Sleep is a powerful weapon in this fight.