In 2013, Americans spent about 60 billion dollars on
products and services related to weight loss (1). This number includes everything from
gym memberships to diet soda. That is a lot of resources devoted to weight loss
and yet we continue to see high obesity rates here in the U.S. According to the Center for Disease Control (2):
- 69% of adults (people 20 years of age and older) are overweight or obese;
- 18.4% of 12-19 years old are obese;
- 18.0% of children 6-11 years of age are obese;
- and 12.1% of children 2-5 years of age are obese.
Resources
- Williams, G. (Jan 2, 2013) The heavy price of losing weight. US News and World Report. http://money.usnews.com/money/personal-finance/articles/2013/01/02/the-heavy-price-of-losing-weight, Accessed 10/27/2014
- Center for Disease Control and Prevention. (May 14, 2014). FastStats - Obesity and Overweight http://www.cdc.gov/nchs/fastats/obesity-overweight.htm, Accessed 10/27/2014.
What is a "healthy" body weight?
Discovering and accepting your healthy body weight is an individual and evolving process. It requires looking at multiple components in your life as well as an openness to accepting different stages of your life. Additionally, it involves a willingness to re-evaluate how you prioritize some numbers.
The following list contains important questions to consider when finding your healthy body weight:
- What is your family's history of disease? Specifically, do you have a family history of:
- hypertension (high blood pressure)
- heart disease
- cardiovascular disease
- dyslipidemia (low HDL, high LDL, high total cholesterol, high triglycerides)
- type 2 diabetes
- What is your personal weight history?
- Were you overweight as a child?
- Have you been overweight or underweight as an adult?
- Do you have a history of an eating disorder?
- Have you been on diets or participated in weight-loss programs? If so, did you regain weight? Did you regain more than you lost?
- Have you had children? Did you return to your pre-baby weight?
- What is your lifestyle like?
- Are you physically active?
- Do you walk to work, drive to work, bicycle, take a bus, etc?
- Do you engage in physical activity like exercise and/or sports activities?
- As an adult, what is the lowest weight you achieved and maintained for at least a year without feeling constantly hungry?
- How do you feel most of the time?
- What is the status of your current metabolic health?
- What is your blood pressure and resting heart rate?
- What is your HDL (good) cholesterol, LDL (bad) cholesterol, total cholesterol, and triglycerides?
- What is your fasted blood glucose? Have you been told you have insulin resistance, pre-diabetes, or are diabetic?
- On average, how many hours a night do you sleep?
- Do you nap during the day? If so how much sleep do you get form naps?
- Do you have enough energy during the day?
- What is your current body weight?
"Body Mass Index, BMI"
What is BMI?
The body mass index (BMI) is a number calculated based on
height and weight. The calculated value reflects body fatness. BMI accurately predicts body fatness for most people.
There are many different BMI calculators available online. You will find that they all work the same and will give you the same numerical result as long as you input the same data. Pay attention to the units of measure that the program requests because sometimes it asks for weight and height in pounds and inches, sometimes it wants height in feet and inches, and sometimes it wants weight in kilograms and height in centimeters. There are websites that provide interpretive information. The quality of that information varies. Here are links to two BMI calculators from reputable sources:
What is the purpose of using BMI as a screening tool?
The purpose of identifying people or populations at risk of disease is to offer early intervention or treatment to improve individual and community outcomes and quality of life. We know that overweight and obesity is associated with low-grade inflammation throughout the body. This inflammation increases the risk of chronic diseases such as cardiovascular disease and type 2 diabetes. Additionally, diets high in saturated fats and cholesterol increase the risk of hypertension and cardiovascular disease. Body weight and BMI are quick and simple ways to identify people and groups that are at greater risk of disease. This helps doctors and public health officials reach out to them.
Body weight and BMI are components of a larger diagnostic picture. Alone these measures cannot diagnose, treat, or prevent any disease. Blood pressure readings, heart rate, blood cholesterol panels and blood glucose tests are common and routine screenings that together with body weight and BMI help health care teams and public health officials understand an individual's or community's health status.
When BMI was introduced into the health care and public health setting, it was not intended to be used by the general public as it is today. As I have said, on its own, the value of BMI is limited. But our access to BMI calculators and BMI charts is endless.
Changing the focus to Metabolic Health from body weight and BMI
We lack successful methods to support long term success for weight loss. At this time, 5-10% of people who lose weight maintain their weight loss for 5 years or more, and 1/3 of people who lose weight regain it within a year (1). We need to keep working to figure this out. We also need to reexamine our approach to weight loss and question if using weight focused goals that emphasize BMI is truly the best way to impact change and promote health (2).
The BMI calculation is not complicated and there are online calculators all over the Internet that make it even simpler. What used to be done by dietitians is done by everybody. We now have personal fitness apps with numerous features to help someone work their way towards their weight-targeted goals. I get it. Body weight and BMI are quick, easy, and inexpensive measures to assess and track. We are a results oriented society and if you increase physical activity and decrease caloric intake, you will see body weight go down. I know, easier said than done, but the numbers will change if you can do it. Doing it safely is less easy. Being able to do it and and then maintain it are other issues. People are complicated, messy, and carry a lot of baggage.
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By jans canon [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
The viscious weight loss cycle of losing-gaining-losing weight has negative effects on health that include
- increased body fatness in the upper body (associated with more inflammation and greater health risk);
- reduced HDL (good) cholesterol;
- decreased muscle mass;
- and varying degrees of psychological harm.
Along with others, I promote metabolic health (2). Achieving metabolic fitness includes adequate nutrition, physical activity, rest/sleep, and stress management. For some people, this journey may involve weight loss. For some people, it may not. These components are far more important than a number on a scale and a BMI classification.
Resources
- Kraschnewski JL, Boan J, Esposito J, Sherwood NE, Lehman EB, Kephart DK, Sciamanna CN.(2010) Long-term weight loss maintenance in the United States. Int J Obes, 34: 1644–1654.
- Bacon L and Aphramor L, (2011) Weight science: Evaluating the evidence for a paradigm shift. Nutr J, 10:9.
Is there a healthy amount of body fat?
A healthy range of body fat varies by gender; in the U.S., the healthy range for adult men is between 8-24% and for adult women is between 21-35%. The risk of developing chronic diseases such as hypertension (high blood pressure), cardiovascular disease, dyslipidemia (low HDL, high LDL, high triglycerides, high total cholesterol), and type 2 diabetes increases when body fat exceeds the healthy range. There are also health risks associated with not having enough body fat, however, that is not the focus of this blog post.
What matters?
Your overall metabolic health matters and it is influenced by multiple factors:
- Blood pressure
- Heart rate
- Fasted blood glucose
- Cholesterol: LDL-cholesterol, HDL-cholesterol, Total cholesterol
- For more information about cholesterol as well as links to other resources
- Triglycerides
- Physical activity
- Sleep per day (6-8 hours per day are recommended for adults)
- Adequate nutrition
- Body weight, BMI
- For those people whose BMI classification places them in the overweight or obese category:
- losing 5-10% of body weight may improve blood pressure, heart rate, blood glucose, and cholesterol levels.
- Weight loss is considered safe at 1-2 lbs per week through a combination of calorie reduction (250 - 500 cals/day) and increased physical activity (250-500 cals/day extra)
Some physicians also look at other parameters because of their role in obesity-associated inflammation and disease risk. If you have blood work done, you might see any of the following included in your lab results. These proteins are altered with obesity and inflammation and when metabolic health is improving, these proteins start to normalize. CRP is the most likely protein that you could see included, but the others are starting to show up as well.
- C-reactive protein (CRP)
- Interleukin-6 (IL-6)
- Adiponectin
- Leptin
- Plasminogen activating inhibitor (PAI-1)
For information about metabolism, please check out the post Some Simple Truths about Metabolism.
Ethnic Differences that Influence BMI and Risk of Disease
There are ethnic differences that impact cutoff values related to obesity and disease risk. It is unclear why this is, but it is clear that these differences exist. The World Health Organization continues to work to address this and it is reflected in their BMI tables. Different countries have different cutoff values to help to try to identify those at risk of disease before disease manifest.
Resources:
- Obesity and Prevention Source, Ethnic Differences in BMI and Disease Risk. http://www.hsph.harvard.edu/obesity-prevention-source/ethnic-differences-in-bmi-and-disease-risk/ Accessed 10/27/2014.
- Chiu, M., Austin, P. C., Manuel, D. G., Shah, B. R., & Tu, J. V. (2011). Deriving Ethnic-Specific BMI Cutoff Points for Assessing Diabetes Risk. Diabetes Care, 34(8), 1741-1748.
Final Thoughts
As Halloween kicks-off another holiday season inevitably followed by heartfelt, well-intended resolutions to lose 10 or 15 pounds, only eat healthy foods, and go to the gym 5 days a week, I wish for us to take a moment and reflect on a few things.
- Many of us have enough to eat to be able to consider altering how we eat, when eat it, and how we're going to cook it.
- What is the motivation behind losing weight? Is it to improve an aspect of metabolic health, physical appearance, or a combination of the two? Whatever the motivation, consider the possibility that focusing on physical activity and mindful eating / eating with awareness might help you move farther along a more satisfying path.
- BMI is used as a screening tool to help people live healthier, longer lives. I think we overuse and over-rely on weight-focused goals and targets including and especially BMI. Many people respond to weight challenges, weight classifications, and weight focused goals with feelings of stress, anxiety, and frustration. I am not sure it makes sense or is productive, especially when the ultimate goal is to improve overall health.
