Most are familiar with the typical cautionary statement, “please consult with your physician before using this exercise equipment or beginning any exercise program.” It’s a well-intended message designed to be responsible and keep people safe.
But scientists called for public warnings with exactly the opposite message at a satellite symposium that was organized by the American Society for Nutrition on Friday, April 25. The event, sponsored by Herbalife Nutrition Institute, took place at Experimental Biology in San Diego.
Endocrinologist Dr. David Heber, director of the UCLA Center for Human Nutrition, reminded that a sedentary lifestyle has disastrous pathologic consequences. He said that, combined with obesity, physical inactivity leads to abdominal adiposity, visceral fat, chronic systemic inflammation, insulin resistance, and ultimately diabetes and cardiovascular disease.
Underlining the consequence of protein breakdown due to physical inactivity, Dr. Heber counseled that the muscle loss and a subsequent drop in resting metabolic rate puts the U.S. population at risk of widespread sarcopenic obesity. Muscle burns 30 Kcals per kilogram versus fat’s only 6 Kcals per kilogram, he reminds.
Former U.S. surgeon general Dr. Richard Carmona said that the problems of getting people to do more for their health wasn’t a matter of needing more knowledge or authority. “It’s getting people to listen,” he said. “Where we have failed is really in the translation. We need better translators of science.”
Sharing some of his 2002-2006 term experiences, Dr. Carmona illustrated how obesity was burdensome to the country by ways of high costs — and even to national security. After Hurricane Katrina, for example, he said a lot of the people affected had low health literacy, were obese, and had several medical conditions related to obesity such as high blood pressure and type 2 diabetes. These issues exacerbated the tragic event.
“Obesity doesn’t get the attention it deserves,” he said. “Health care is really sick care and it’s driven by obesity.”
University of Colorado Professor of Pediatrics and Medicine James Hill, Ph.D., said regular physical activity of an hour or more daily was one of the behaviors that has shown to be key in leading to long-term weight management success, according to the National Weight Control Registry of which he co-founded. The registry follows more than 6,000 formerly obese people who have lost weight and kept it off permanently.
But the reason physical activity is important had little to do with burned calories, he explained. “In my opinion,” he said, “the important point is that it helps our bodies operate in the way they’re meant to operate.”
Hill said once physical activity reaches a specific threshold it has a way of adjusting the body’s appetite according to energy expenditure. Showing a figure modified from the work of Jean Mayer and colleagues, he illustrated the concept of the physical activity threshold explaining that to the left of the bar was an unregulated zone and to the right there was a regulated zone.
“Our biology works best at high level of physical activity. Energy expenditure is driving the bus,” he said. “But most of us are left of the bar.”
Most now includes 88.9 percent of the world population in 122 countries, according to professor of epidemiology and kinesiology Bill Kohl, Ph.D., of University of Texas at Austin’s Department of Kinesiology and Health Education.
In July 2012, Kohl reported conclusions in The Lancet that one out of three (31.1 percent) adults didn’t meet physical activity guidelines of 150 minutes per week, that men were more active than women, that inactivity increases with age, that inactivity is higher in high-income countries. In addition, he found that four out of five (80.3 percent) adolescents didn’t meet guidelines of 60 minutes per day and that boys were more active than girls.
Throughout the world, Kohl said, overall physical activity is declining rapidly. He cited research of Timothy Church and colleagues, as well as a review paper by Shu Wen Ng and Barry Popkin, showing that one of the major reasons had to do with drastically declining from occupational physical activity.
“I submit to you that this isn’t just a weight loss problem,” he said. “It’s a pandemic. If the number of people in the world that were physically inactive were smoking, we’d be up in arms. We should be up in arms.”
How much physical activity should one do to gain an impact? There’s a dose-response effect, according to John Jakicic, Ph.D., professor and chair of the University of Pittsburgh department of health and physical activity.
Based on his prior research and from Goodpaster et al and Slentz et al (and unpublished data he shared), he said that the higher level of physical activity one has, the greater the body weight change, the greater impact on visceral adiposity, and greater reduction of HbA1c (glycated hemoglobin).
Rather than put up warnings about exercise, he said, why not put up a new cautionary statement: “Physical inactivity has been shown to be associated with increased mortality, morbidity, and lower quality of life. Please consult with your physician if you decide not to engage in regular periods of daily physical activity.”
Dr. Julian Alvarez Garcia of University of Alicante (Spain), reminded that exercise is a “very complex phenomenon.” Athletes, for example, will often time nutrition before, during, or after exercise to fuel specific adaptations such as for weight loss, endurance, or strength.
Moving what he called “a step beyond energetics,” Dr. Garcia suggests that a different mindset be used when eating. We shouldn’t think of nutrition as feeding exercise, but “feeding adaptation,” he said.