18.2 Measures of Health and Their Limitations

We may receive messages about bodies—our own or others—in the form of information from doctors, nurses, personal trainers, medical charts, and other sources. This information might include measurements like weight, body mass index, or other measures of body composition or relative shape—sometimes referred to as apple or pear shape. While some health risk can be associated with certain measures, many of the most common metrics and indicators used do not, in fact, tell us much about one’s overall health and wellness.

Weight

Weight is one measure people commonly associate with health risk, and while weight can be a consideration, many other factors are more closely associated with health risks and diseases, such as:

• High blood pressure
• High LDL cholesterol
• Physical inactivity
• Tobacco use
• Heavy alcohol consumption
• High blood glucose
• High triglycerides

In fact, repeated fluctuations in weight—like those experienced by someone who repeatedly goes on and off weight loss programs—may actually be to blame for more of these health risks than simply being overweight or obese (Strohacker & McFarlin, 2010).

Although weight does provide some evidence of one’s energy intake and energy expenditure, weight is not a simple function of “calories in and calories out.” For example, stress releases cortisol, which changes the way the body metabolizes glucose. Constant release of cortisol increases the risk of developing insulin resistance, which elevates blood sugar and can impact weight gain (Geer, Islam, & Buettner, 2014). Also, weight also does not provide context to one’s health behaviors. For instance, weight does not tell us the types of food a person consumes or how physically active they are.

Body Mass Index

Body mass index—or BMI—is calculated using a person’s weight and height, and is intended to communicate whether a person has a healthy amount of body fat. It is a popular measure used in medicine and public health because, compared to other methods of measuring and communicating a person’s body composition, it is noninvasive, inexpensive, and simple to calculate. However, BMI has many limitations, and the way the categories are arranged and labeled can be misleading and problematic. For example, a BMI between 18.5 and 25 is considered “normal or healthy weight” and a BMI of 25 to 30 is considered “overweight,” but these do not necessarily provide context to one’s actual state of health or wellbeing. Many factors, such as sex, age, and muscle mass, can influence one’s actual body composition and BMI does not account for this; BMI does not distinguish fat from muscle, bones, and other things that make up the body. For example, BMI might overestimate body fat in athletes and others with a muscular build, and it often underestimates body fat in older people. Further, it has been proven that the correlation between weight and cardiometabolic diseases varies between racial and ethnic groups. So when BMI is used as part of a screening for cardiometabolic health, people in some groups may be overlooked. This means they might go longer with underlying diseases that could be treated if properly diagnosed. According to the CDC (2017), while it can be useful as a screening tool for obesity and its related health concerns and is used to compare one population to another, BMI is not an accurate description of the true body composition or health of an individual.

Appearance

Misperceptions exist both across cultures and associated with current aesthetic trends about various ways appearance may be a measure of health. One common misconception in some cultural spaces is that an appearance of being slim or slender equates to good health, and that being larger equates to poor health. However, this is also not the case. For example, while someone might be slender, appearance does not provide information about biomarkers, such as blood glucose levels and blood pressure. Assumptions of any kind based on appearance can lead to harmful stereotyping. Discrimination and negative attitudes based on appearance and body size and shape is well-documented (Puhl & Brownell, 2001; Puhl & Latner, 2007). What messages have you heard in your culture about the association between appearance and health? Do you see ways that you’ve been influenced to make generalizations about health based on appearance?

You can not make assumptions about your own health or the health of others based on weight, appearance, or BMI.