Clinical Perspectives
Obesity’s impact
A North American perspective By Paula Stewart The fact that North America is becoming increasingly obese is well recognized. What remains unclear is exactly why this has occurred in the latter half of the 20th century and the first half of the 21st-century. And what are the health implications of this growing epidemic?
E
pidemiologic records indicate that the obesity epidemic really began with the end of the Second World War. At that time, food preparation became industrialized and convenience foods became the hallmark of the modern family. There was also the rise of fast food loaded with calories, carbohydrates, harmful fats, and production beef, i.e. beef produced with estrogen implants to increase weight at the market 1,2. Additionally, in the 1960s and 70s, there was an awareness of the role of cholesterol in heart disease and therefore the low-fat diet acquired widespread endorsement. The fats removed from foods in production were replaced by sugars, most often fructose3. Only now are we recognizing the negative effects of fructose (as well as artificial sweeteners) on weight gain and the development of obesity4. These changes in our food intake and food production, combined with changes in our physical activity have accelerated the obesity epidemic. North America has embraced an increasingly sedentary lifestyle. There has been the rise of energy saving aids such as escalators, elevators, driving, TV as a leisure activity, video games, and delivery services
USA and Canada BMI Classifications Classification
United States BMI Category (kg/m2)
Underweight <18.5 Healthy (normal) weight to height
18–24.9
18.5 – 24.9
Overweight
25.0 – 29.9
Overweight: (Class I)
25-29.9
30.0 – 34.9
Obese: (Class II)
30-39.9
35.0 – 39.9
Morbidly obese: (Class III)
40-49.9
< = 40
Super morbid obese
50 +
for everything imaginable. To effectively communicate about obesity there must be a recognized way to measure it. The body mass index (BMI), although flawed, is most widely accepted. This is the: weight (kilogram) / height (meters 2). There are slight variations in the classifications between the USA and Canada (see chart above). Changes in food production and an increased sedentary lifestyle have resulted in
Paula Stewart, MD, MS, CLT-LANA received her undergraduate and Master degrees from Stanford University. She attended medical school at the University of Minnesota in Minneapolis and completed her residency in Physical Medicine and Rehabilitation at the Mayo Clinic. Dr. Stewart co-founded LANA, The Lymphology Association of North America, and now serves as Vice president on the executive board. Dr. Stewart is currently in the process of developing a lymphedema outpatient clinic in the Chattanooga, Tennessee region.
Fa l l 2 0 1 9
Canada BMI Category (kg/m2)
overweight levels increasing from 44% of the US population in 1960 to 66% of the population in 2004. Obesity increased within that same timeframe from 13% to 32%. More alarming is the increase in childhood obesity from 4% in 6 to 11-year-olds in 1971, to 19% in 20075. Childhood obesity is especially concerning because of the risk of associated health issues that increase with the length of time obesity has been present. Pediatricians are noting that rates of Type II diabetes, hypertension, fatty liver disease, gallstones and heart disease risk are soaring in children6. Complications of obesity in adults include increased mortality due to diabetes, heart disease, stroke and cancer, pregnancy complications, increased surgical risk, and psychological disorders such as depression. Increased annual medical costs related to obesity disorders are estimated to be in excess of $117 billion per year. Ly m p h e d e m a p a t h w a y s . c a 5