Childhood obesity is an urgent and complex problem, and its relationship with poor sleep poses a major public health challenge. Adequate sleep is a critical foundation for good health in general.

Poor sleep quality and short sleep duration are linked to being overweight and obese in children as well as adults. Childhood and adolescent obesity have been associated with significant complications, including obstructive sleep apnea, asthma, type 2 diabetes mellitus, hypertension, abnormal lipid levels, liver disease, and depression.

Since childhood obesity is linked to adult obesity, identifying and treating modifiable factors like sleep issues is critical. In this article, I highlight the impact of sleep on childhood obesity. Note that these points also apply to adults!

How does poor sleep contribute to obesity?

Based on the National Sleep Foundation, sleep needs vary by age. Infants need 12-16 hours, 1-2-year-olds need 11-14 hours, preschool kids need 10-13 hours, school-age children need 9-11 hours, and teens need 8-10 hours of sleep.

Most children in the US get less than the recommended sleep hours, with 57% of middle school kids and 73% of high school kids getting inadequate sleep.

Short sleep duration is associated with a high risk of being overweight or obese. In addition, a meta-analysis of 22 studies showed that short sleepers had over 2 times increased risk of being overweight or obese.

There are four ways poor sleep leads to obesity:

1. Changes in hormone regulation: Poor sleep can lead to changes in hormone regulation and increased calorie consumption. Two hormones regulate our appetite; leptin, and ghrelin. Ghrelin is a hunger hormone that lets us know we are hungry. Poor sleep patterns and inadequate sleep cause decreased leptin and increased ghrelin, leading to increased eating. Poor sleep can also cause changes in our body’s cortisol level, leading to increased stress and inflammation.

2. Changes in diet quality: Short sleep duration leads to unhealthy diet habits, including larger portions, increased perceived hunger, and higher-calorie choices, including sugary foods. In a survey of over 2000 4th and 7th graders with insufficient sleep, there was more frequent soda consumption and fewer vegetables.

3. Decreased physical activity and motivation: When children have poor sleep, they tend to be more physically inactive, have more sedentary lifestyles, and reduced motivation which can lead to weight gain. This is particularly common in older children. For example, a study on sleep duration in kids showed that those with insufficient sleep were likely to not meet the physical activity guidelines of 60 minutes per day. Instead, these children spent more time watching TV, using screens, and snacking.

4. Increased food intake to fight fatigue: Sometimes, to counter the fatigue, children (and adults) with sleep loss try to make up with increased caloric intake, which may not necessarily be driven by hormonal changes.

While most studies focus on sleep duration, sleep quality, and timing can also contribute to obesity.

Sleep timing and obesity

Our circadian rhythm (or internal clock) plays a significant role in our hormonal and metabolic health. Teens and young adults experience a change in their circadian rhythm during puberty, with a natural tendency to fall asleep and wake up later.

Combined with competing school work demands, caffeine use, and increased screen time on social media, they are in a constant state of social jetlag. As a result, their circadian rhythm is misaligned with the social and environmental clock. Social jetlag is also associated with increased consumption of unhealthy snacks and caffeine late at night since they are awake. This tends to alter their eating patterns and metabolism. They are also more likely to skip breakfast and engage in after-dinner snacking.

Medical sleep disorders and obesity

Finally, sleep disorders and obesity are strongly connected.

Obstructive sleep apnea (OSA), a condition of repeated upper airway obstruction during sleep, leads to disrupted sleep quality. If left untreated, OSA can cause learning and behavior problems, hypertension, obesity, and other harmful effects in children.

Previously, OSA in children was mainly due to large tonsils and adenoids. While this is still the most common cause, obesity is becoming a major culprit. With obesity, excess body weight leads to more fat crowding around the neck and tongue, causing the upper airway to collapse. This is similar to what is seen in adults. The relationship between obesity and OSA in children is probably bidirectional, as children with OSA have poor sleep quality, which increases the risk of obesity due to all the hormone and inflammatory changes. This can increase the chance of worsening OSA. More research needs to be done to better understand this.

Another sleep condition associated with obesity is narcolepsy, which presents with excessive daytime sleepiness, suddenly decreased muscle tone (cataplexy), hallucinations, and disrupted night sleep. The cause of obesity in narcolepsy is not completely clear but it seems to be related to the loss of a neurotransmitter (a brain chemical messenger) called orexin, which may decrease their metabolism and increase their appetite.

How do we address the pandemic of poor sleep and obesity?

Make sleep a priority for the family.

Ensure your children are getting the recommended sleep hours by age.

Practice healthy sleep habits:

• Have a consistent sleep time and wake time.

• Ensure a bedtime routine that is age-appropriate.

• Maintain a cool, dark, and quiet sleep environment.

• Limit electronic device use to about 30 to 60 minutes before bedtime.

• Limit caffeine intake.

• Avoid heavy meals and late-night snacking.

Encourage physical activity aiming for at least 60 minutes per day.

Advocate for policy changes around making schools start later for teens. This will better align school times with their circadian rhythm.

Watch out for any symptoms consistent with a medical sleep problem like sleep apnea, which can fragment sleep. Reach out to their doctors if you have any concerns about your child’s sleep.

Sleep loss and poor quality can lead to childhood obesity. Children who aren’t sleeping enough may experience the same hormonal changes seen in adults that lead to weight gain. They could also experience increased daytime fatigue, leading to decreased physical activity. Addressing sleep issues early in children can help decrease these negative effects.

Interested in additional sleep support? Learn more about Sleep Coaching and our Private Practice The Restful Sleep Place.