Childhood obesity describes when a child or adolescent is well above the normal weight for his or her age and height. Recent studies indicate that obesity in childhood greatly increases the risk for early-onset of several obesity-related diseases including heart disease, high blood pressure, and type 2 diabetes. In addition to getting an early start on the road to poor health, studies also indicate that being obese when you are young makes you more likely to be obese as an adult.

While still relatively rare in developing countries, childhood obesity is a growing problem in the Western world. According to the National Center for Health Statistics, the prevalence of overweight and obesity has nearly tripled in the U.S. for all child and adolescent age groups since the late 1970s. For young children aged 2-5 years, an estimated 5% were overweight thirty years ago; now that figure is 14%. For children between 6 and 11 years, the prevalence increased from 6.5% to nearly 19% in that same span. The percentage of overweight adolescents between 12 and 19 years increased from 5% then to more that 17% now. Overall, an estimated 15-20% of all children and adolescents are overweight or obese.

Here’s a sobering thought: type 2 diabetes, which is caused by insulin resistance and is strongly associated with obesity, used to be called “adult-onset” diabetes to differentiate it from type 1 diabetes, which is unrelated to obesity. However, so many children are now developing type 2 diabetes that the term “adult-onset” has been dropped completely.

The body mass index or BMI that relates height with weight is used to determine childhood obesity as it is in adults, with the added provision that age is also a factor for children (because the amount of body fat changes with age). After determining a child’s height and weight, established national BMI-for-age growth charts can be used to determine a child’s BMI. For children, the important measure is the BMI percentile, meaning the percent of children of the same sex and age who have a lower BMI. While different organizations sometimes use slightly different definitions of what is considered overweight, according to the U.S. Centers for Disease Control and Prevention (CDC), children with a BMI-for-age between the 85th and 94th percentiles are considered at risk for being overweight, while those with a BMI-for-age at the 95th percentile or above are considered overweight or obese. However, because children are still growing and there tends to be much variation among body types even among children of the same age, only a doctor can truly determine if a child is overweight.

If a child or adolescent is overweight, the most likely cause is some combination of overeating and inactivity. Even though children may need to consume more calories than adults to fuel their body’s growth, the fundamental relationship between energy intake and expenditure still holds: take in more energy than you use and you will gain weight. If you are concerned that your child may be overweight, talk to his or her pediatrician. A doctor can help evaluate your child’s weight and overall health and determine if he or she should lose weight.

For children who need to lose weight, the weight loss should be slow and steady, between a pound per week and a pound per month depending on the child’s age, body type and overall health. The methods for losing or maintaining weight are the same as in adults: eat less and move around more. Lifestyle changes that include a balanced healthy diet, lower caloric intake, and increased physical activity are the keys to losing weight and keeping it off. One of the best strategies to help a child lose excess weight is to improve the diet and exercise levels of the entire family. If everyone around them is doing it, it will be much easier for a child to make lasting healthy changes.

If your child is not overweight but you are concerned about the potential that he or she may become overweight, there are some things you can do to help prevent this situation. You can take them for yearly visits with the doctor. You can set a good example by eating right yourself and exercising regularly to maintain your own weight. Even better, you can fix them healthy meals and keep only nutritious foods around the house. You can also enroll your child in sports or other types of organized physical activity they might enjoy.

There are also some behavioral things you can do to help prevent childhood weight problems. For one, try to avoid power struggles involving food. While many parents may say things like “no dessert until you finish your vegetables,” in general using food as a reward or punishment is not recommended because children can easily develop unhealthy behavioral issues about food that you never intended. Along these same lines, it is also important to avoid focusing too much attention on your child’s eating habits and weight. If the basis of your relationship with your child revolves around their weight, it can cause psychological wounds that may make the child less able to handle stress, more likely to gain and retain excess weight, and more prone to developing an eating disorder.