Obesity: Why Talk About It?

By now, many Americans have heard about the obesity epidemic, and about the health consequences and economic consequences of this epidemic.  For a variety of very valid reasons (such as fears of contributing to eating disorders or fueling size prejudice) some people are more comfortable talking about nutrition and physical activity than about obesity.  When it comes to crafting public health messages – especially those targeting children and youth – focusing on healthy eating and physical activity (and not necessarily on weight) can be a positive approach.  It is, however, important for adult partners to understand that, like nutrition and physical activity, fat is a health concern in and of itself.

Many of the Montanans who drafted this obesity prevention plan view healthy nutrition, healthy physical activity, and healthy weight maintenance as equally important legs of a three-legged stool.  All want to help without harming, and all are focused on finding ways to make the healthy choice the easy choice.  Most of this plan focuses on describing the numerous benefits of good nutrition and regular physical activity and on ways to promote these behaviors.  This is the only part of the plan specifically addressing the importance of maintenance of a healthy weight.

Adults:

According to the National Institutes of Health (NIH), an adult with a Body Mass Index (BMI) of 18.5–24.9 is considered “healthy,” while a person with a BMI of 25–29.9 is considered to be “overweight”, and someone with a BMI equal to or greater than 30 is “obese.”  BMI is a weight/height calculation used to approximate body fat content.  (To learn more about BMI or to calculate your BMI go to http://www.cdc.gov/healthyweight/assessing/bmi.)

Obesity is associated with numerous health problems including: coronary heart disease; type 2 diabetes; cancer (endometrial, breast, and colon); high blood pressure; high cholesterol or high levels of triglycerides; stroke; liver and gallbladder disease; sleep apnea and respiratory problems; osteoarthritis; abnormal menses; and infertility. Most scientists in the Division of Nutrition, Physical Activity and Obesity at the US Centers for Disease Control and Prevention (CDC) agree that excess body fat is an independent risk factor for disease and premature death. Regardless of one’s diet and level of physical activity, the risk of type 2 diabetes increases at a BMI of 25, and escalates as BMI increases.

Since the 1950s, scientists have been researching the ways in which obesity leads to illness. We now know that fat cells are not passive storage compartments, but actually manufacture many hormones; some peptides made by fat can create changes in a person’s immune function. In particular, the pathway from obesity to insulin resistance is of intense interest to the public health field, since insulin resistance is the first metabolic problem that appears in many diseases, including type 2 diabetes and polycystic ovary disease. While preventing obesity is understood to be a way to reduce the rates of a host of other diseases, it will be some time before the connections between obesity to specific diseases will be fully known.

Some concepts to keep in mind are:

  • Having a BMI in the “healthy” range doesn’t automatically mean that a person is healthy. A person’s healthy weight may, or may not, be the result of a healthy lifestyle. This is particularly true for someone whose weight is impacted by harmful behaviors such as smoking, binging/purging, or using drugs — all of which lower one’s weight and BMI in dangerous ways.
  • Being “overweight” may, or may not, mean prioritizing weight loss as a goal. NIH’s guidelines recommend weight loss for an adult whose BMI is over 25 and who have a waist circumference of more than 35 inches, or who have a BMI over 25 and two or more other risk factors (such as hypertension, dyslipidemia, elevated blood glucose) at a rate of 1-2 pounds per week. The NIH recommends weight loss be achieved by consuming a balanced diet with fewer calories and, ideally, moving more. Otherwise, the guidelines call for maintaining weight at or below the present level, explaining that these overweight patient’s “ health risk, while higher than that of a person with a BMI < 25, is only moderately increased.”  
  • An overweight individual’s biggest risk may be for further weight gain, since most of us add pounds as we age.  Over time, this can add up to a significant amount of weight. The more obese a person is, the more likely she or he is to face health problems and possibly to die prematurely, so people in the “obese” ranges should talk with their health care provider to assess their risks and set appropriate health goals.
  • Depending on one’s culture, the weight that is considered sexy and desirable might be below — or above — what the BMI chart specifies as “healthy”.
  • For some people, losing enough weight to move into the “healthy” BMI range is just not realistic. It’s important to remember that losing even 10% of one’s body weight can produce health benefits for those who are overweight.

Right now, there is no way to know exactly how many Montana men and women are overweight or obese.  The gold standard for tracking overweight and obesity is the National Health and Nutrition Examination Survey (NHANES).  Staff of NHANES actually weigh and measure a random sample of Americans, and NHANES data show that, after having risen dramatically, overweight and obesity rates have leveled off over the last decade nationwide in most segments of the population.  Unfortunately, NHANES data is not reported by state.  The best data we have for adults in Montana comes from the Behavioral Risk Factor Surveillance System (BRFSS).  The BRFSS is a telephone survey that asks people to self-report about a variety of factors.  Because it uses self-reported data, it is much less reliable than surveys like the NHANES that use measured data.  The Montana BRFSS shows that adults continue to report heights and weights that translate to increasing BMIs. Whether this change in reporting behavior is a result of actual changes in body weight or is a result of some other factor is not possible to say.   Based on BRFFS data, however, in 2009, 38.4% of Montana adults were overweight, and an additional 23.7% were obese.  In other words, approximately two out of every three men and women in Montana are above a healthy weight.  Although it may not be possible to pinpoint a precise number, a review of all the data available strongly suggests that rates of overweight and obesity in Montana put our state’s residents at risk.

Children:

Nearly one-fifth of American children ages 2-19 years old are categorized as obese.  From the early 1970s to 2007-2008, obesity rates doubled (from 5% to 10%) among children ages 2 to 5 years, tripled (from 5% to 17%) among teens ages 12-19, and quadrupled (from 4% to 19%) among children ages 6 to 11.  Recent data suggest that obesity prevalence among children may be leveling off since 2000, however other data suggest that severe obesity among children and adolescents is increasing.   

Childhood obesity is not a benign condition, as it is associated with premature death and adulthood disease. For example, one study followed 4857 Native American non-diabetic children to determine which of four risk factors—BMI, cholesterolemia, blood pressure, or glucose tolerance—best predicted early death from disease. The study followed the children for more than 20 years, during which period there were 559 deaths, of which 166 were suitable for the analysis.  Of the factors studied, high BMI alone predicted premature death by endogenous causes; glucose intolerance, high blood pressure and hypercholesterolemia alone failed to significantly predict premature death.  Furthermore, obesity in youth strongly predicted premature death even after a statistical adjustment to control for development of type 2 diabetes in adulthood.  The most obese children were more than twice as likely to die prematurely.

The Institute of Medicine (IOM) has estimated the national costs for illness related to childhood obesity per se to be $14 billion. In addition to type 2 diabetes, other so-called “adult” diseases such as sleep apnea, hypertension, dyslipidemia, hepatic steatosis and are becoming more commonplace among the obese pediatric population —a circumstance unheard of 30 years ago, before the upsurge in childhood obesity prevalence.  And obesity in childhood persists into adulthood. Among older children, obesity is an increasingly important predictor of adult obesity.

Unlike states that require BMI testing among school children, Montana has little data on obesity rates among this state’s children except for that collected through self-reports of high school students through the Youth Risk Behavior Survey.  According to these data, however, 10.4% of Montana high schools students were obese in 2009, and an additional 11.9% were overweight.
                                                                                                               
BMI for children is not calculated in the same way it is calculated for adults.  Instead, BMI calculations for children take into account their age and gender, and then compare them to other children in terms of a normal growth curve.  The term “obese” refers to children and youth with a BMI equal to or greater than the age- and sex-specific 95th percentile on the BMI growth charts issued by the CDC in 2000.  Children whose age- and sex-specific BMI percentile falls between the 85th and 95th percentiles are classified as overweight.  (Earlier sources will designate children who meet the 95th percentile definition as “overweight” because of concern about the stigma attached to the word “obese” and also because some overweight children are large, but not overly fat; children between the 85th and 95th percentiles were formerly considered “at risk” for obesity.)