Shape Up America! — From 1994 to Now
George L. Blackburn, MD, PhD
In 1994, C. Everett Koop and I, two surgeons with a career-long interest in nutrition medicine, helped develop the Shape Up America! guide, “On Your Way to Fitness.” That document was based on the premise that if people eat sensibly, exercise regularly, and lose a few pounds, those small lifestyle changes will pay off in big ways — lower blood pressure, reduced cholesterol levels, and less need for health care services as well as increased independence, productivity, and energy.
That message is as true now as it was then, and applies equally to men, women, and children of every ethnic and socioeconomic group. But over the last 18 years, the body of science on obesity, weight loss, and weight maintenance has not only grown exponentially, but also changed dramatically.
The focus of Shape Up America! remains on redefining weight management by encouraging increased physical activity and healthy eating for all Americans. These key messages are cornerstones of treatment that can help prevent weight gain or achieve lasting weight loss. But not everyone is able to make these lifestyle changes, and obesity remains a worldwide medical crisis despite extensive and diverse efforts to address it.
Science has been making great strides toward finding new solutions and approaches to the treatment and prevention of obesity. To date, work on the mechanisms of weight loss maintenance has been focused on two main areas of study, each independent from the other. One is metabolic/endocrine research; it has identified changes in appetite hormones, particularly a decrease in leptin levels, as critical players in the physiological drive to regain lost weight. The other is the study of psychology/behavior; it suggests that something other than physiology is going on when people maintain substantial weight loss over long periods of time.
Formerly obese people in the National Weight Control Registry have overcome powerful metabolic and neuroendocrine forces to maintain weight loss (i.e., 30-pounds for one year or longer). Two components contribute to their success — bottom up/hormonal-driven behavior and top-down/neurobehavioral activity. Few studies have tried to integrate the two fields or understand how they interact. This makes them particularly intriguing.
Leading edge research seeks to find out whether it's possible to enhance the brain circuits that trigger cognitive/inhibitory control over food. Two new technologies put answers within reach — functional brain imaging and noninvasive brain modulation. The first has shown that after a 10% body weight loss, brain responses to visual food cues shift toward overactivity in reward-related and cognitive/inhibitory control areas — a neural signature of vulnerability to overeating. People in the National Weight Control Registry show a more balanced pattern of brain activation in those regions.
The second technology, noninvasive brain modulation or Transcranial Direct Current Stimulation (tDCS), is a procedure that uses weak electrical currents applied to the head to enhance brain activity. It is inexpensive, easy to administer, portable, and painless. Researchers will use it to find out the causes of top-down neurobehavioral effects. What they learn can provide the basic knowledge needed for future development of novel obesity-related neurotechnologies, i.e., those at the intersection of neuroscience and engineering.
Pioneering research will integrate three levels of study: clinical, physiological, and neuroscientific. It will examine physiological influences in two directions — metabolism-to-brain (bottom-up) and brain-to-metabolism (top-down). For the first time, it will simultaneously assess changes in body weight, subjective appetite, and hormones, while the third factor (neurobehavioral) is experimentally manipulated.
Neurobehavioral research into how to enhance brain circuits that promote inhibitory/control over food choices represents a new paradigm that will enhance our insights into the mechanisms that affect successful weight loss and maintenance in obese patients. At the same time, it will pave the way for a new modality of brain-based approaches for the treatment of obesity.
Although methods of research are in the process of radical change, the original message of Shape Up America! is as sound now as it was when we developed “On Your Way to Fitness.” 18 years ago. Losing weight and maintaining that loss over time require increased physical activity and healthy food choices. The more and better ways we have to help greater numbers of people achieve those ends, the sooner we'll be able to prevent obesity and reverse its ill effects among the millions of Americans who suffer from it.