American College of Physicians: Internal Medicine — Doctors for Adults ®

Tuesday, November 5, 2013

Our weight is not a choice

Our weight, of course, is substantially influenced by our behaviors and choices. I have argued for years, against a backdrop of exotic theories, genetic discoveries, and snake-oil hucksterism, that weight represents energy balance, and is thus overwhelmingly influenced by calories in and calories out. I have made the case along the way that yes, a calorie is a calorie.

But I immediately append something I know abundantly from my clinical experience: Two people can eat about the same, and exercise about the same, and one gets fat and the other stays thin. This absolutely does happen; it is the truth. It’s not fair, but who ever told us life would be? Bad stuff does at times happen to thin people, too, and that isn’t necessarily fair either.

We don’t know all the reasons for accelerated weight gain, or weight loss resistance, but we do know some, and they are the usual suspects. There are important gene variants, to some extent associated with ethnic variation, that influence metabolic rate. There are marked differences in resting energy expenditure, with some individuals, and some whole populations such as the Pima Indians, and the Samoans, noteworthy for extreme “fuel efficiency.” Fuel efficiency fostered survival when calories were scarce and physical activity unavoidable; in modern context, it fosters obesity and its sequelae.

We are also learning more, almost every day it seems, about the important influence of our resident bacteria on our weight, as well as our overall health. Variations in gut microbes can substantially alter the fate of the calories we take in, and our propensity for weight gain.

Note that none of this, nor any other exotic theory such as the potential for viruses to cause obesity, alters the fundamental importance of energy balance. If person A has a lower resting energy expenditure than person B, it means that, all things being equal, person A will gain weight more readily and from fewer calories. But that simply indicates that all things shouldn’t be equal; person A needs fewer calories. There is inter-individual variation in the equilibrium point for energy balance, where calories in match calories out; but there is such an equilibrium point for us all, and when we find it and honor it, our weight is stable. We need to accept this and deal with it, just as we deal with all other inter-individual variation. Variation in the size of our feet requires corresponding variation in our selection of shoes.

Weight is powerfully influenced, but not directly determined, by our behavioral choices. Some people, making all the right choices, will be heavier than others making the same, or even less good, choices. And people making good lifestyle choices, including routine exercise, are apt to be fit even if they remain somewhat fat, and will be far better off than those who are either fat or thin, but unfit.

As we foray ever further into an age of incentives and disincentives to nudge people toward better health and lower disease-care costs, it becomes urgently timely to acknowledge that weight is not a behavior. Body mass index is often included among the metrics considered for the application of such nudges in health promotion programming. I think that’s wrong. What if two people commit just the same efforts to improving their diets and physical activity, but one loses weight more readily than the other. Is there any rationale for a different application of rewards or penalties? In my view, if someone is relatively resistant to weight loss and is then penalized financially for this “handicap,” it is the literal addition of insult to injury (or vice versa).

The causes of epidemic obesity are all around us. We don’t want to get carried away with invoking genes or resting metabolic rate to explain obesity at the population level. A half century ago, human beings were the same as they are now; our genes, and metabolisms, were all but identical then as now. Yet rates of obesity are staggeringly different. You can’t account for a change in Y with an X that has been constant; if X explains a change in Y, it must be because X has also changed. The changes that account for obesity in the modern world reside in the modern world, not in the relative constancy of human physiology.

But human physiology absolutely does account for variations among us. All members of a common species, we Homo sapiens are more alike than different; but we can be pretty different just the same. Some of us, for instance, are white and some are black. Mostly that is a trivial difference, skin deep. But skin pigment is just the veneer over a compelling tale of survival.

Once, we were all black. But then the great human diaspora expanded our habitat into areas where sunlight was a less abundant resource. Black skin made ample vitamin D in the tropics, but not so in the northern reaches of the temperate zone. So a mutation resulting in fair skin that also happened to confer an ability to make more vitamin D with less sunlight provided a survival advantage, and all of us here today without our native skin pigment are progeny of that original mutation.

In just the same way, different experiences in different parts of the world favored genetic mutations selectively, resulting in greater or lesser energy efficiency, and other variations in metabolism influencing the propensity to gain, retain, or lose weight. Clearly almost all of us are vulnerable to the obesigenic influences of the modern world, but some of us are far more vulnerable than others. All of us can lose weight when calories in are less than calories out, but it takes very differing efforts for some of us than for others to get there from here.

A half century ago, more or less, obesity was rare. That’s not because people had different genes then. It’s not because there were better people, with more self-discipline, back in those good old days. It’s because a vast array of obesigenic changes have populated the world around us in the past five decades.

Ideally, this would change, and we would devise a modern world that cultivates our health and weight control, rather than conspiring against them. Collectively, we can make that happen, and I believe we will, eventually. But it’s a slow process; don’t hold your breath.

In the interim, it takes skills to be lean and healthy. Those skills can be acquired, and they can do the job.

But even with the consistent application of the same skill set, weights will vary. Weight is only partially determined by factors under our control. As we look around and size one another up, we have to stop thinking that variation in size means variation in effort. Belts and bathroom scales do not measure effort, resolve or determination, let alone anything remotely like human worth.

This is an exciting time for me, with the release of my new book, Disease-Proof. Honestly, I think it’s a very good book; and I also think it’s very important that it is a totally honest book. It’s honest about the incredible power of lifestyle choices to reshape our bodies and our health. It’s honest about what it takes to get there from here. I hope, and believe, that we have all had enough of false promises and magical thinking, and are ready to apply the practical magic of skill-power to ourselves and our families. Disease-Proof is a delivery vehicle for just that skill-power.

But since Disease-Proof emphasizes the transformational power of our behavioral choices over health and weight, it seems an important time to note, as I do from every podium I visit, that weight is neither a behavior, nor a choice. Nobody wakes up and decides what to weigh.

We do indeed have stunning potential control over our health, and should make better use of it. Our feet and forks are, or should be, the master levers of medical destiny. But even the best application of skill-power will not turn weight into a behavior. Weight is not a choice, and we should all choose to recognize that.

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.

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Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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