More than 70% of American adults are either overweight or obese, and more than 30% of U.S. children are overweight or obese. Obesity raises the risk of several diseases (type 2 diabetes, heart disease, high blood pressure, osteoarthritis, and cancer), so it is not surprising that the estimated annual healthcare cost of obesity in the United States is nearly $200 billion. During session 081, “Are We Doing Enough About Obesity? An Interactive Discussion of Evidence-Based Weight Management Strategies,” on Tuesday, July 19, speakers discussed the causes of obesity and strategies to reverse its prevalence. Susan Raatz of the U.S. Dept. of Agriculture began by stating that the mortality ratio in the United States rises with increasing body mass index. In particular, there is an increased risk of cardiometabolic mortality as body weight increases. So it is important to stem the causes of obesity. But this is not easy because the causes of obesity vary from behavior genetics (dietary preference, inclination to exercise), to metabolic factors (metabolic rate, thyroid function), to environmental factors (excessive energy intake, reduced physical activity).
Two of the biggest factors contributing to expanding waistlines are reduced physical activity and increased caloric intake. Reduced physical activity encompasses society’s tendency to drive instead of walk, take escalators instead of climbing stairs, and sit for most of the day instead of engaging in physical movement. Moreover, people’s inclination to build convenience into every aspect of their lives is putting them at risk for obesity and obesity-related disorders. “All of the things we do in our life that are time-saving and energy-saving cause our weight to increase,” Raatz said.
High-calorie intake also plays a significant role in energy imbalance. When people eat and drink more calories than they burn, over time they gain weight and become either overweight or obese. In extreme cases, people even become morbidly obese, which is defined as being more than 100 pounds over ideal weight or having a BMI of 40 or higher. Raatz said that carbohydrates frequently receive the bulk of the blame for high-energy diets. People often call high energy foods “high carb” regardless of whether the foods are really high in carbohydrates.
Another popular term used to categorize carbohydrates is the glycemic index: Foods with a high glycemic index are considered bad dietary choices. According to Ratz, the glycemic index was designed to help diabetics make better food choices; it is not an indication of a food’s nutritional value. Calories may count, but so do nutrients. Raatz therefore does not think carbohydrates contribute to weight management issues; in fact, research indicates that high-fiber diets benefit weight management. It’s more likely the fat and sugar in foods such as cookies, cake, and pastries that causes people to become overweight or obese, she said.
As bad as obesity is on adults, it can be even worse for children, but not in the same way. Melinda Sothern of Louisiana State University pointed out that in adults, the higher the fat content of the liver, the higher the level of inflammation. But in prepubescent children, excess fat in the liver is not linked to inflammation, Sothern said. And while extreme obesity limits physical mobility and causes discomfort in all demographics, it takes a greater toll on children—putting too much stress on the growth plate, causing poor bone growth and musculoskeletal health, and setting them up for a lifetime of sedentary activities. Playing outdoors, which is occurring less and less in today’s digital-obsessed society, is imperative for children as it promotes physical activity, increases bone strength, and improves mood, Sothern said. She suggests turning on the stereo instead of the television so that children can dance instead of sitting and watching television; walking together as a family after dinner; dropping media devices in a box by the door and playing outside before homework.
Sothern and Raatz both hope to see more advances in obesity research and treatment to reduce excess weight in adults and children.