Wide girths are widespread

Over the past three decades, child and teenage overweight and obesity levels have tripled in the developed world. The data is sobering. Current estimates are that about 15 percent of American children and teenagers are overweight, and about 17 percent of young people are obese.

Puppy fat is tenacious

The prevalence is of medical, social and – Michelle Obama might add – political concern because puppy and adolescent fat tend to be tenacious. For example, overweight and obese preschoolers are much more likely than their normal-weight peers to become obese teenagers and obese adults.

And, it’s not just their waistlines that are at risk. The cumulative effects of continuous obesity can result in serious diseases like heart disease and type 2 diabetes. There are also associated psycho-social problems such as physical dissatisfaction and inhibition, peer prejudice and peer abuse.

What’s up with waistlines?

The causes for this worrisome level of weight gain is one we’ve heard many times before: Too much energy in and too little energy out. For those few young overweight people who heed expert advice to cut down on fats and sugar and ramp up exercise, the focus is, of course, in the right direction.

But, there’s another important factor that’s gaining robust research traction: Sleep hygiene; the quantity and quality of young people’s sleep.

Obesity and sleep curtailment converge

There is a mounting body of evidence to show that young people with poor sleep hygiene are significantly weightier than their peers who have good sleep hygiene habits. And, unfortunately, in general young people’s sleep habits are trending in the direction of poor sleep hygiene.

Sleep losses

Overall, Gen Z has less sleep now than their counterparts in previous generations. Some sleep scientists blame the technology revolution for their relatively poor sleep hygiene while others refer to our children’s hurried lives. Still others fault their levels of caffeine consumption.

In addition to screens, hurriedness and caffeine, sleep researchers tend to agree that nowadays parents have relatively permissive attitudes to their children’s sleep hygiene. Research convincingly shows that when parents neglect to supervise and monitor their children’s sleep habits, their children’s sleep suffers.

Greg’s a good example

Twelve year old Greg’s habits support research outcomes. He’s an amicable, softly spoken, large person.

Based on a calculation that includes his weight and height, his body mass index (BMI) is on the 87th percentile. He’s overweight and headed for the 95th percentile point, which would place him in the obese range.

He tells me that he exercises at school daily, during the Physical Education hour, but that he seldom feels “puffed out”.

Greg doesn’t eat at school, and nobody minds. Gone are the days when, after a scheduled lunchtime, primary teachers checked their students’ lunch boxes for bread crusts.

At home, like so many of his normal-weight peers, he watches TV or plays video games for 3-4 hours between mid-afternoon and bedtime. He takes breaks now and then to snack on high fat, high sugar foods that will replenish the glucose that he’s lost through the stress of neutralising baddies and protecting his avatar.

Greg’s dinner is delayed because his parents cook it when they return from work in the evening. In the meantime, he’s allowed to drink Coke Zero or a Diet Coca-Cola because his parents are home and he’s overweight.

After dinner, which he hardly eats, he completes whatever is left of his homework. Greg contends that he should relax once he’s done, by playing more video games. By the time he leaves his game, he’s also hungry because he hasn’t eaten dinner. So, once again, he snacks.

And, because his parents are too exhausted to argue against his sleep resistance, Greg’s bedtime is pushed back arbitrarily, so that he has no regular sleep onset schedule. He seldom sleeps for more than 8.5 hours a night. Bear in mind that, based on his age, his recommended sleep duration is 10 hours a night.

Moreover, Greg seldom sleeps through the night. He’s been assessed for sleep apnoea and anxiety and given the all-clear. His family is functional and intact, so these factors are unlikely to play a role in his dysfunctional sleep patterns.

He does have a TV set in his bedroom, though, and a laptop with multi-player gaming platforms. Beside his bed is his phone, replete with multi-player gaming apps. He can play internationally at any time of night through different time zones, as he sheepishly told me he “sometimes” does. There’s also his pre-sleep consumption of caffeinated Coca-Cola to consider.

So what’s sleep got to do with it?

At least 7 things

1. Young people with poor sleep hygiene, like Greg, tend to have weight-gaining eating habits. They eat more overall simply because there’s more time for them to eat.

2. They’re not only very tired on awakening, they’re also hungrier, especially for foods that are high in fats and sugars. And, they seem to have slower metabolic rates than those who have good sleep hygiene.

3. Greg’s late nights mean that he has later morning awakenings, and consequently, pandemonium prevails until he arrives at school. So, he doesn’t eat breakfast. And, recall that he also doesn’t eat lunch.

No surprises that he’s “starving” when he returns home. Because he’s exhausted and very hungry, he continuously snacks on comfort food, high in fat and sugar.

4. He’s also mentally and physically exhausted because he suffers from a chronic sleep deficit. So he busies himself with undemanding but captivating sedentary activities; video games and television viewing.

5. Sleep conserves energy. The less sleep, the higher one’s net energy expenditure, some young clients remind me. But, even though Greg’s energy expenditure is increased by his sleep deficit, the situation doesn’t translate into weight loss. He doesn’t lose weight because his energy debt is probably offset by his continuous afternoon and evening binge.

6. His insatiable appetite is also thought to be tied to hormonal imbalances caused by his sleep deprivation. When Greg awakens through his deep sleep phase, his body reacts with a fight or flight system response that is associated with an increased dose of glucose and a variety of hormones. This occurs to pump body muscles for action. Greg’s lying in bed, however, so he’s not expending the energy. Unfortunately, the fight-flight secretions are associated with increased fat deposit, particularly around his waist.

In addition, experts believe that Greg’s poor sleep hygiene affects the discharge of hormones that are associated with appetite regulation. For example, leptin is an appetite regulator that is secreted during sleep. Its levels decrease with insufficient sleep and disrupted sleep. At the same time, there’s an increase in ghrelin secretions, a hormone that increases hunger and food intake. So, with poor sleep hygiene, Greg is much more likely to feel famished than full.

7. Little wonder then, that he snacks through the day. Unfortunately, thanks to the leptin-ghrelin hormonal imbalance (among other factors), he’s likely to eat much more than he needs. He’s too tired to exercise, so the more he eats, the more the extra kilojoules are deposited around his middle. For these reasons, among others, Greg is overweight and headed for obesity.

Young people and obesity: Food, exercise, sleep

Given Greg’s lifestyle, it’s not surprising that he’s drifting in a dangerous direction. He’s not alone. The statistics on child and teenage obesity rates are troubling.

So what are Greg’s parents to do to protect him from the risk factors that plague his generation? They probably know that they could more closely supervise and monitor his food intake and his exercise. They might not realise, though, that it would be in Greg’s interests for them to supervise and monitor his sleep as well.

To read more about sleep and other issues relevant to young people, visit  QANDAKIDS at drjennifersmith.com.au