Of the many statistics about childhood obesity, one in particular highlights the urgency of the problem: One of every three children in America is now considered overweight or obese, and childhood obesity has more than tripled in the past 30 years. How did we get to this place? And even more important, how do we stop the growth of this epidemic?
Being obese or overweight is determined by a percentile measurement of Body Mass Index (BMI), which uses height and weight to determine if a person is normal, underweight, overweight or obese. The BMI is an indirect estimate of body fat that is valid for most individuals. Since children grow in height as well as weight, the standards for children need to be matched for age and sex. A BMI-for-age of 30 places a child in the 95th percentile, the determining number for obesity. A BMI-for-age of 25, or at the 85th percentile, is considered overweight.
A child who qualifies for the 95th percentile is advised to have an in-depth medical assessment since this amount of body fat is also associated with high blood pressure, elevated levels of lipids (fats) in the blood and an increased potential for obesity-related diseases that include type-2 diabetes, asthma, hypertension, high cholesterol, liver and gall bladder disease, bone and joint problems, and sleep apnea. It is also linked to a range of social and psychological issues including poor self-esteem, depression, withdrawal and poor peer relationships.
But as complex as the causes of childhood obesity are, the baseline equation is simple: Too few calories are being burned for the amount of calories being consumed. What's complicated is that this calculation is mediated by a host of behavioral, environmental and genetic factors.
Heredity contributes a risk factor of 5 to 40 percent for obesity, and studies indicate that 50 to 70 percent of a person's BMI is determined by genetic influences. If both parents are overweight, the children have a 75 percent chance of being obese. If one parent is obese, the probability is 25 to 50 percent. But while the connection between genetics and obesity has been established, the problem is usually caused by multiple genes interacting with environmental and behavioral factors. Given that the genetic characteristics of a population change slowly, the rapid weight increases in America show that skyrocketing obesity rates are probably due to behavioral and environmental factors combining with genetic factors, rather than genetic predisposition alone. The upside is that making some basic changes in lifestyle and nutrition can make a big difference.
One of the biggest culprits is a sedentary lifestyle dominated by TV watching, computer activities and video games. It's estimated that American kids are spending 25 percent of their day watching television, and that those who log the most TV hours have the highest rate of obesity. First, because they're not burning enough calories, and second because they're usually eating unhealthy snacks while they're watching.
What they're watching is also a factor. A March 2007 study found that kids age 2 to 7 see an average of 12 food ads every day, while kids age 8 to 12 see 21 ads, and teens view up to 17 food ads daily. As Dr. Margo Wootan of the Center for Science in the Public Interest says, "If companies were marketing bananas and broccoli, we wouldn't be concerned, but ... most marketing is for sugary cereals, fast food, snack foods and candy." A 2006 study showed that for each additional hour of television viewing, kids consumed 167 extra calories. So it's obvious that limiting TV time is one of the best health care decisions you can make for your family.
A healthy focus on nutrition can't be underestimated. Hectic schedules, both for kids and parents, have resulted in a decline in breakfasts and an increase in dinners outside the home. Use of fast food restaurants with their high calorie, high salt and high fat and carbohydrate entrees, along with their super-sized, sugary soft drinks, is a big contributor to our current obesity epidemic, especially among the lower socioeconomic groups.
Supervising mealtimes will help you control what your kids eat and create an opportunity to offer encouragement. It's also important to cut down on the snacking, as well as on processed, pre-prepared food. Making healthy foods easily accessible is key, so have fresh fruit washed and ready to eat in a big bowl where everyone can reach it. Same with washed and cut vegetables and low-calorie dip. What you eat is important, too, because kids develop preferences based on foods their parents eat.
As discussed in last week's blog on sleep, shortened duration of sleep is associated with weight gain and obesity. So making sure that your child avoids sleep deprivation is an important step in combating overweight and obesity.
For parents, be a role model, not a nag. Eat healthy yourself and get lots of exercise. The family will follow your lead, especially if you turn exercise like bike riding and rollerblading into family outings. (Not hang gliding, though.) Introduce healthy changes gradually. Go from serving whole milk to two percent, and then to skim milk. Keep portion sizes moderate, eat from smaller plates and skip seconds. Instead of frying, better to grill, steam or bake. And try to establish a regular eating schedule for the whole family.
Out and About
Walk instead of drive whenever you can and take the stairs instead of the elevator. Look for a parking space farther from the store, and walk. At the store, select the checkout line with the batteries and the gift cards, not the candy. At restaurants, skip the buffet and choose low-fat, low-sodium or heart healthy dishes.
Childhood obesity is a problem that's not only influenced by what your kids eat, but also by how the family lives. And given that overweight adolescents have a 70 percent chance of becoming overweight adults, the time to address childhood obesity is today. It's easier than you think. Next week, we'll talk about how new skills at the grocery store can impact the health of your whole family.