(& Not Just About Weight)
BMI or Body Mass Index was developed in 1871, and was implemented to help determine if an adult’s weight was appropriate for their height (Mahan, Escott-Stump, & Raymond, 2012; Schlenker & Roth, 2011).
Although BMI does not directly measure body fat, it has a high correlation with the amount of fat in the body. Usually, the higher the BMI, the more fat the person carries. However, BMI does not account for higher weight due to an increase in muscle mass as opposed to fat, so this correlation is not always accurate (Mahan et al., 2012; Schlenker & Roth, 2011).
A person’s BMI can be an indication of several factors, including under-nutrition, over-nutrition, and obesity, and these may tell us clues about our health. In this week’s article I will tell you about these factors. I will, however, start with telling you more about BMI.
The formula to calculate BMI is:
BMI = weight (in kg) / height2 (in m)
If an adult’s BMI is less than 18.5 they are considered underweight, if it is between 18.5 and 24 it is normal, if it is between 25 and 29 they are overweight, and if it is higher than 30 they are obese (Mahan et al., 2012).
A BMI over 25 indicates a person is overweight or obese, and thus is at risk of developing health problems. Health risks associated with higher BMI values include hypertension, type-2-diabetes, coronary heart disease, asthma, and arthritis (Stommel & Schoenborn, 2010).
However, this does not apply to everyone. A study evaluated the prevalence of chronic conditions in the United States (US) over a ten-year period amongst non-Hispanic whites, African Americans, Hispanics, and East Asians Americans (Chinese, Japanese, Korean, and Vietnamese descendents). African Americans had a higher prevalence of hypertension, diabetes, and asthma, while non-Hispanic whites had a higher prevalence of coronary heart disease and arthritis. East Asians had the lowest prevalence of all diseases (Stommel & Schoenborn, 2010).
These statistics do not indicate the level of risk for a person to develop these conditions because everybody’s circumstances are different. Nonetheless, statistics support that a high BMI is associated with a higher risk of developing health problems. When looking at the US population in general, 28% of adults with a BMI between 28 and 29 had hypertension, 7% had diabetes, 5% had coronary heart disease, 9% had asthma, and 11% had arthritis (Stommel & Schoenborn, 2010).
BMI and Under-nutrition
Under-nutrition occurs when people have marginal nutrition status. That is, they consume enough nutrients to stay alive, but not enough to sustain physiological demands to heal from injury or illness, carry a healthy pregnancy, or grow and develop properly. A person with under-nutrition typically has a lower BMI, but this is not always the case (Mahan et al., 2012).
Mild forms of under-nutrition occur when individuals follow poor eating habits and do not consume enough calcium, vitamins, fiber, or fruits and vegetables, and instead consume high amounts of fat. This happens when people rely on fast foods for sustenance; eat a lot of processed or sugary foods; consume large amounts of soft drinks or sports drinks; or when they drink large quantities of alcohol (Mahan et al., 2012).
Severe forms of under-nutrition occur during famine or illness when people are simply unable to get any type of nourishment. All forms of under-nutrition can leave a person more susceptible to illness, disease, and malnutrition (Mahan et al., 2012).
BMI and Over-nutrition
Over-nutrition occurs when there is excessive nutritional intake, and is usually associated with a higher BMI. Over-nutrition occurs when people consume too many nutrients and simultaneously do not engage in enough physical activity, often resulting in weight gain (Mahan et al., 2012).
Over-nutrition occurs when people eat too much food or macronutrients, such as carbohydrates, fats, and proteins, as well as too many micronutrients, such as vitamins and minerals. Micronutrients can also be taken as herbal supplements, where the supplement provides more vitamins and minerals than the body requires, and can result in tissue damage, interference in the body’s metabolism, and/or interference in absorption of other nutrients (Mahan et al., 2012).
Usually, over-nutrition results in overweight conditions, obesity, type-2-diabetes, and cardiovascular disease. Over-nutrition can also make a person more susceptible to other diseases (Mahan et al., 2012).
BMI and Obesity
BMI over 30 is associated with obesity. However, BMI is not the only consideration. It is evaluated along with weight, waist circumference, waist-to-hip ratio, and the presence of co-morbid conditions, such as diabetes and hypertension (Rippe, Crossley & Ringer, 1998).
Obesity itself is a chronic disease caused by many factors such as genes, the environment, a person’s metabolism, their lifestyle, and their behavior. It is an epidemic that affects many. The World Health Organization (WHO) considers obesity as “one of the greatest neglected public health problems of our time” (Rippe et al., 1998). Obesity is linked with coronary heart disease, cardiovascular disease, type-2-diabetes, glucose intolerance, hyperinsulinemia, hypertension, sleep apnea, dyslipidemia, osteoarthritis, and other chronic diseases (Rippe et al., 1998; Thompson, 2017).
The rate of obesity in the United States is on the rise. The current estimate says that 40% of adults are obese, compared to 30% in the year 2000 (Thompson, 2017). In addition, 18.5% of all children aged between 2 and 19 are obese, compared to nearly 14% in 2000. As a result, children are now suffering from illnesses that were thought to only affect adults, such as type-2-diabetes, high blood pressure, cholesterol, and liver disease (Thompson, 2017).
There are several factors that affect obesity, which include:
A low-grade systemic inflammation known as metaflammation, which is triggered by the body’s metabolism, is associated with obesity and other chronic diseases (Egger & Dixon, 2009). Metaflammation differs from classic inflammation in that it does not involve pain, redness, swelling, and heat. Instead, it affects the whole body, and can go undetected while it perpetuates disease. It is induced by inactivity or low activity, stress, smoking, sleep deprivation, weight gain, fasting, over-nutrition, and excessive consumption of alcohol, fat, sugars, refined carbohydrates, and salt (Egger & Dixon, 2009).
We have an increased tendency to lead sedentary lives. Technology dominates our lives in many ways, and even from a young age, it is common to find kids sitting in front of a tablet playing games. We have decreased involvement in physical activity. However, consumption of food has not decreased. In fact, it may have increased. This imbalance between food consumed and physical activity has contributed to the rise of obesity.
This includes a rise in fast food restaurants. These are often more readily available than grocery stores. In addition, restaurants have increased portion sizes, making people believe that the grossly enlarged servings they receive at restaurants are what they should be consuming normally. Often, people consume in one meal more than the caloric intake they should have in one day. Increase in intake of juices, sodas, and carbonated drinks that are high in sugar and add empty calories to the diet, has also contributed to obesity.
There are certain drugs that increase appetite and can cause weight gain, and have also contributed to obesity. These include antihistamines, steroids, relaxants, and anti-depressants.
Exposure to toxins, such as MSG that is frequently added to Chinese and other fast food, have also been found to increase obesity by having an effect on metabolic rate.
Extra weight in the abdomen is a greater risk for obesity than extra weight on the hips or thighs. A waist circumference higher than 88 cm or 35 inches is often an indication of a higher risk for chronic disease (Schlenker & Roth, 2011).
Intestinal bacteria may affect obesity. It is believed that people who are obese have less diverse gut microbes than do those who are thin (Wallis, 2014).
Action to Take
Although weight is not the only factor affecting obesity, weight loss on its own has been shown to reduce the risk of associated diseases. For instance, a weight loss of 5% to 10% has improved glucose intolerance and type-2-diabetes. In addition, weight loss has lowered blood pressure (Rippe et al., 1998).
Reversing the factors that affect obesity, such as reduced alcohol intake, lifestyle changes, increased exercise, weight loss, smoking cessation, and moderate and adequate food consumption that is higher in fiber, whole grains, fruits, vegetables, and lean meats will help treat disease and reduce obesity (Egger & Dixon, 2009).
It is important to develop a plan to make sure our BMI tells a healthy story. Focus not only on the frequency of exercise, but also on the intensity. Consume organic fruits and vegetables, whole grains, lean proteins, and drink plenty of water. Consider the quantity of food consumed, reduce portion sizes, and reduce intake of sugars and processed foods. Also, reduce exposure to toxins and intake of drugs and unnecessary supplements, and increase gut bacteria. Monitor progress by recording what is eaten and the exercise done to make sure not to consume more than what is required for physical needs.
Egger, G. & Dixon, J. (2009). Obesity and chronic disease: always offender or often just accomplice? British Journal of Nutrition, 102(8), 1238-1242. Retrieved from https://doi.org/10.1017/S0007114509371676
Mahan, L. K., Escott-Stump, S., & Raymond, J. L. (2012). Krause’s Food and The Nutrition Care Process (13th ed.). St. Louis, MO: Elsevier Saunders.
Schlenker, E. D. & Roth, S. L. (2011). Williams’ Essentials of Nutrition and Diet Therapy- Revised Reprint (10th ed.). St. Louis, MO: Elsevier Mosby.
Rippe, J. M., Crossley, S., & Ringer, R. (1998). Obesity as a chronic disease: Modern medical and lifestyle management. American Dietetic Association Journal of the American Dietetic Association, S9-15. Retrieved from http://search.proquest.com/docview/218392019?accountid=158302
Stommel, M., & Schoenborn, C. A. (2010). Variations in BMI and prevalence of health risks in diverse racial and ethnic populations. Obesity, 18(9), 1821-1826. doi:http://dx.doi.org/10.1038/oby.2009.472
Thompson, D. (2017). Nearly 4 in 10 U.S. adults now obese. MedicineNet. Retrieved on October 18 2017 from https://www.medicinenet.com/script/main/art.asp?articlekey=207576&ecd=mnl_day_101317
Wallis, C. (2014). How gut bacteria help make us fat and thin. Scientific American. Retrieved on October 18, 2017 from https://www.scientificamerican.com/article/how-gut-bacteria-help-make-us-fat-and-thin/