Scott Kahan, MD, MPH is a physician specializing in both clinical obesity medicine and public health. He is the Director of the National Center for Weight and Wellness in Washington, DC, Medical Director of the Strategies To Overcome and Prevent (STOP) Obesity Alliance at George Washington University, and Chair of the Clinical Committee for The Obesity Society. He serves on the faculties of the Johns Hopkins Bloomberg School of Public Health and the George Washington University Schools of Medicine and Public Health. He serves on the Board of Directors of the American Board of Obesity Medicine, The Obesity Society, Obesity Action Coalition, and Obesity Treatment Foundation.
Dr. Kahan received his undergraduate degree in bioengineering from Columbia University, his medical degree from the Medical College of Pennsylvania, and his residency and Masters of Public Health degree from Johns Hopkins University. Dr. Kahan has advised the White House, U.S. Congress, U.S. Food and Drug Administration (FDA), Centers for Medicare and Medicaid Services (CMS), several Surgeons General, and numerous national and local advocacy groups on public health initiatives pertaining to obesity, nutrition, and chronic disease prevention. He has published more than 100 scientific articles, textbook chapters, and textbooks in the areas of medicine, obesity, and public health, and he is a scientific peer-reviewer for more than 50 academic research journals. He is a frequent contributor to numerous media outlets, including NPR, USA Today, NY Times, CNN, Washington Post, Fox, Huffington Post, and others.
Q & A with Scott:
Q: What drew you to public health and preventive medicine?
A: In medical school, I wasn’t as passionate about medicine as I thought I’d be. I remember feeling jealous of many of my classmates who were so laser-focused on becoming this-or-that type of doctor. I was excited to be there and loved what I was learning, but I had a strong pull toward thinking about larger populations. I’d spent the year before teaching in an inner-city high school in New York, so I’d been consumed with many of the broader societal problems that affect health outcomes – such as socioeconomic disparities, poor nutrition, and adverse childhood experiences. After a few years of going along in the traditional medicine path, these interests ultimately pulled me toward preventive medicine, which is a specialty that is essentially a combination of clinical medicine and public health. I signed on at Johns Hopkins and began doing work on chronic disease prevention, nutrition, and then obesity. To this day, my career continues to be a mix of clinical medicine – focused on obesity treatment, nutrition, and behavioral medicine – combined with public health, in which I work on public health and policy research on obesity prevention and treatment, as well as workforce training and advocacy.
Q: What is the official definition of obesity as opposed to overweight?
A: Clinically, obesity is defined as body mass index (BMI) greater than 30 kg/m² and overweight as BMI between 25 and 30 kg/m². BMI is a way of standardizing weight to account for differences in height. It’s a useful screening measurement but tends to misclassify many people as having a healthy weight when, in fact, they are frail and actually have excess body weight (BMI can also misclassify some very fit, muscular people as overweight, but this is relatively uncommon). In practice, however, the clinical definition above is very limiting. You can be heavy but engage in lots of healthful behaviors and have the benefit of good genetics, and therefore you may have little or no increased health risk despite the excess weight. Similarly, being thin doesn’t guarantee good health, nor are all (or even most) thin people engaging in healthful behaviors. BMI alone can be misleading, for both patients and clinicians. A better approach is to think about obesity as excess weight that is associated with health issues, for which size (ie, BMI) is just one of many factors. Several systematic frameworks to redefine obesity and overweight in this way are in development. Nonetheless, I feel the need to mention that whether a person is thin, heavy, or whatever, it’s not a measure of who they are as a person, and we shouldn’t make assumptions about their behaviors, health status, or character based on appearance. Weight stigma is one of the most common and misunderstood – and harmful – aspects of the obesity epidemic.
Q: We all know that there are a multitude of health issues that can arise from obesity, but what medical conditions associated with obesity impact the onset of diabetes or complications during management?
A: Your question leads to a really important point – many people take for granted that it is now commonly accepted that obesity is a serious health issue. This is a recent shift. Prior to the last decade or two, it was far more common to think of obesity as an aesthetic issue. This was true even for physicians. Traditionally, physicians did not consider obesity to be a medically-relevant issue, and they rarely counseled patients about weight or nutrition. Thankfully, this has been changing. My team recently published an important study showing that primary care physicians and nurse practitioners now overwhelmingly consider obesity to be a health issue and 97% (out of 1500) said that they have a responsibility to work with their patients on obesity and weight issues. And, we have a study coming out that shows there is evidence for 236 diseases linked to obesity. Diabetes, sure. High blood pressure, sure. But also hundreds of others. Two dozen cancers related to obesity and diseases of every part of the body. Obesity doesn’t only increase the risk for diabetes…it overwhelmingly increases this risk. Gaining just a few pounds, on average, doubles the risk for diabetes, and once you get to a BMI around 35 kg/m² – about 70 lbs overweight – risk for developing type 2 diabetes is literally dozens-fold higher. One Harvard study showed 90-times increased risk for type 2 diabetes in heavier men. This is why diabetes rates are still increasing. In part, due to the inflammation caused by obesity, insulin function is blunted, thereby worsening the control of blood sugar. Moreover, obesity begets obesity and diabetes. That is, several studies show that obesity likely causes inflammation and disturbance of neurons in the brain that are responsible for appetite and satiety, so as you gain weight, it becomes even harder to manage healthy eating and prevent further weight gain, all of which further worsens blood sugar control and diabetes.
Another important aspect of weight gain is regarding medications. Many diabetes medications have a common side effect of weight gain – it leads to a backward loop, in which obesity causes diabetes, which may further worsen obesity, and so forth.
Q: As a specialist in your field with an academic and institutional background, what innovations have you
been seeing that have made a difference in obesity prevention?
A: Thinking broadly, an important innovation has been to shift the approach to obesity and diabetes to go beyond just telling people to lose weight and exercise. We talk about an “ecological approach” in public health, in which large, complex health problems are known to have a wide range of causal and influencing factors, and therefore successful strategies need to be similarly broad-based. This means supporting individuals, offering education and evidence-based treatments, but also addressing the environments that surround the individual – such as dealing with the predominantly unhealthy food options in schools and workplaces, taming aggressive junk food marketing, dealing with economic settings that have led to healthy foods being much more expensive, on average, than junk foods, and so forth. (I did a TEDx talk a few years ago on how the food environment drives obesity, in which I compared Shrek to the Surgeon General :). This type of ecological approach is what has led to so much progress in addressing epidemics of tobacco use, motor vehicle deaths, and infectious diseases over the past century. I predict we’ll see similar benefits in addressing obesity and diabetes in the coming decades.
In terms of technical innovations, some things that jump out for me are the development of much better medications to treat obesity physiologically and diabetes medications that not only treat diabetes but also cause weight loss, not gain. Some also prevent heart attacks. This is a big deal! The entrance of large companies with lots of resources and ingenuity into the obesity and diabetes space is great news, too. I’ve worked with a wide range of companies that would not traditionally be expected to be involved in this space – Google, McKinsey, and many others. We already know a lot about what works on a clinical level, these and other key stakeholders are starting to scale it up. They are bringing knowhow on systems engineering, Big Data, and AI to the table. It’s very exciting.
Scott’s Networking Interests:
- Systems scientists who have expertise in integrating the complexity of lots of seemingly disparate pieces into functional systems
- Social scientists and social entrepreneurs, because ultimately these problems are going to boil down to social changes, both on the part of the populations of people affected and also with respect to shifting social and political will to be able to sustain long-term progress on these epidemics
- People who are great at execution, because I strongly believe that folks like Bill Gates, Warren Buffet, Mark Cuban, and Oprah would have become uber-successful at any field they’d have chosen because of how they approach problems and setbacks to get from concept to conclusion.