BMI, Obesity and Weight Management
Normal weight, overweight, and obesity can be measured by body mass index (BMI). BMI is calculated by weight (kg) divided by the square of height (m2) (Jensen-Yanovski et al, 2014).
The table below explains the categories associated with BMI values. Note: In children, obesity is measured as BMI higher than the 95th percentile related to age and sex (Acosta-Aronne et al., 2009).
| Category | BMI |
| Underweight | Less than 18.5 kg/m2 |
| Normal weight | 18.5 to 24.9 kg/m2 |
| Overweight | 25-29.9 kg/m2 |
| Obesity (class 1) | 30-34.9 kg/m2 |
| Obesity (class 2) | 35 to 39.9 kg/m2 |
| Extreme obesity (class 3) | Greater than or equal to 40 kg/m2 |
In the United States, obesity is linked to the top 10 causes of death and associated comorbidities before death (Ogden, Yanovski, Carroll, & Flegal, 2007). Mortality risk increases as BMI increases (Guh- Anis et al., 2009). The 2013 American Heart Association/American College of Cardiology/TOS Obesity Guidelines recommend that patients who are overweight or obese with cardiovascular risk factors, (hypertension, hyperlipidemia, and hyperglycemia), be counseled that lifestyle changes that produce even modest, sustained weight loss of 3-5% produce clinically meaningful health benefits, and that greater weight loss produces greater benefits. This amount of weight loss is likely to result in meaningful reductions in triglycerides, blood glucose, hemoglobin A1C and the risk of developing type 2 diabetes (Jensen et al, 2014).
The American Gastroenterological Association released a white paper in 2017 entitled, POWER – Practice Guide on Obesity and Weight Management, Education and Resources (Acosta et al., 2017). The POWER model presents a continuum of care that is based in 4 phases:
- Assessment
- Intensive weight loss intervention
- Weight stabilization and re-intensification, when needed
- Prevention of weight re-gain
They summarized weight management strategies as follows:
- Nutrition: reduce dietary intake below that required for energy balance by consuming 1200-1500 calories for women and 1500-1800 calories per day for men.
- Physical activity: reach the goal of 10,000 steps or more per day.
- Exercise: reach the goal of 150 minutes or more of cardiovascular exercise per week.
- Limit consumption of liquid calories (i.e, sodas, juices, alcohol, etc.).
- Utilize a tool to support and adhere to the low-calorie food intake.
They recognized that lifestyle changes including reduced calorie diet and physical activity are the cornerstones of treatment, and that medications, bariatric endoscopy and surgery are important tools to help patients with obesity achieve realistic goals.
Read the full white paper to find out more about the phases of care of obesity and weight management, pharmacotherapy, and the different methods of procedural and surgical interventions to address obesity.
References:
Acosta, A., Streett, S., Kroh, M.D., Cheskin, L.J., Saunders, K., Kurian, M.…& Aronne, L. (2017). White Paper AGA: Power- Practice Guide on Obesity and Weight Management, Education, and Resources. Clinical Gastroenterology and Hepatology, 15 (631-649). doi: 10.1016/j.cgh.2016.10.023
Jensen, M.D., Ryan, D.H., Apovian, C.M., Ryan, D., Apovian, C.M., Ard, J.D.…&Yanovski, S.Z. (2014). 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Obesity Society. Journal of the American College of Cardiology, 63(2985-3023). doi: 10.1161/01.cir.0000437739.71477.ee.
Ogden, C.L., Yanovski, S.Z., Carroll, M.D., & Flegal, K.M. (2007). The epidemiology of obesity. Gastroenterology, 132 (2087-102. doi: 10.1053/j.gastro.2007.03.052
Guh, D.P., Zhang, W., Bansback, N., Amarsi, Z., Birmingham, C.L., & Anis, A.H. (2009). The incidence of co-morbidities related to obesity and overweight: A systematic review and meta-analysis. BMC Public Health, 9 (88). doi:10.1186/1471-2458-9-88.ris
