Thursday, December 10, 2015
Junk food: from confusion to clear and simple truth
I was somewhat startled, and quite concerned, to learn directly from the source while sipping coffee together, that my wife was confused by the latest study on junk food, generating headlines such as: “Junk Food Not to Blame for America's Obesity Epidemic.” I was startled because my wife, an expert cook and mother of 5, has become very knowledgeable about nutrition over the years in her own right, because she is highly intelligent and because she is embarrassingly well educated, with a Ph.D. in neuroscience from Princeton. In other words, if she's confused, everybody's confused. That's why I was concerned.
There is no legitimate cause for confusion in this study. Rather, we have painted ourselves into a corner with a plethora of misguided “either, or“ and “action, opposite reaction“ approaches to nutrition that have generated a whole lot of heat while dousing the common light. This is fixable, of course, and the timing is good, because 2 noteworthy fixes are imminently in the offing. We'll get back to those after addressing the new study.
Let's start here: In the contrived context of hyped up and dumbed down “either, or” approaches to diet, weight (and health), junk food causes obesity, or it doesn't.
This new study did not carry out any kind of intervention to answer that question. Rather, using a nationally representative sample of 5,000 adults from a federal survey, researchers looked at intake of candy, soda, and fast food and found little difference between the lean and overweight members of the group. They did, however, find particularly high levels of fast food intake, and the lowest reported intake of vegetables and fruits, in both tails of the bell curve: among the heaviest of the heavy, and among the skinniest. These 2 traits, underweight and severe obesity, have long been strongly associated with adverse health outcomes. In those bad lands, junk food prevails.
But again, across the broad middle of the bell curve, lean and obese were both consuming candy, soda, and fast food at rather high levels, something we have certainly heard before. Does this then prove that fast food is unrelated to obesity, as the clamoring headlines seem to suggest?
Of course not, and a thought experiment will clarify quite readily.
Let's go back in time to the 1950s and ‘60s when nearly half the U.S. population smoked. Now, imagine a nationally representative sample of 5,000 adults at that time, including a large number with, and a certain number without, smoking-related lung disease, such as emphysema. Smoking would be quite prevalent in both groups, because it was so prevalent in the entire population. Those results, if interpreted like the new study about junk food, would result in this headline: “Tobacco not to blame for America's emphysema epidemic.” Given what we now know, and to put it in appropriately blunt terms: That fails to pass the sniff test. It smells bad, like tobacco smoke itself, because it is bad; it's bunk.
Where is the problem with that study? Everywhere.
Unless a “toxin” of any kind is so potent that it produces obvious and nearly immediate harms in absolutely everyone exposed, there will be variation in the effects observed. Some people will be more vulnerable, some less so. Some will succumb quickly, some slowly. Some will show one kind of adverse effect, some will show another.
This is all true for tobacco, and in no way attenuates our certainly about its implication in emphysema, lung cancer, and a long list of other awful things. If everyone in the population smoked, a snapshot of the population at any given time—and that's exactly what the NHANES data used in the new junk food study provide—would show both sick and healthy smokers. The interpretation that tobacco is thus exonerated is not just wrong, but flagrantly and self-evidently so. Rather, it means that: (a) not everyone gets sick from tobacco at the same time; (b) not everyone gets sick from tobacco in the same way; and (c) a comparison of individual health within a population can result in missing the larger truth about the health of the whole population. In a classic illustration of missing the forest for the trees, a compare-and-contrast between apparently sick and apparently healthy smokers in a given population would fail to reveal that the entire population had much more disease than a comparable population of non-smokers.
This is exactly the story for junk food. It doesn't make everyone fat, but we, as a nation, are a whole lot fatter than we would be without it. It doesn't make everyone sick in the same way. In fact, a recent emphasis on the adverse effects of “thin obesity“ is directly germane. Some people with the most dangerous variety of “obesity” do not have an elevated BMI, the measure examined in the new study. Rather, they have a normal BMI, but excess fat around the middle where it does the most mischief. What dietary pattern is associated with that ominous body composition? You guessed it: a junk food laden diet, otherwise known, to our shame, as the typical (or standard) American diet.
There is another important limitation to the new study I have not seen addressed. The researchers defined the trifecta of soda, candy, and fast food as “junk.” Alas, the bounds of comestible American junk extend far beyond those narrow confines. What about breakfast cereals with some kind of sweetener as the first ingredient? What about multicolored marshmallows as part of a complete breakfast? What about cheese puffs and pork rinds; donuts and muffins; toaster pastries, Snackwells, Doritos, and deli meats?
NIH data suggest that roughly half of the calories in the diet of the typical American child come from this broader swathe of foods reasonably catalogued as “junk.” When an exposure is this universal, it becomes virtually impossible to determine its overall impact on a group by comparing those succumbing, to those managing to resist. Another thought experiment should convince you.
This time, we compare survivors and those not so fortunate among the Titanic's passengers. Since exposure to a ship wreck in the North Atlantic did not differ between those who died and those who survived when the ship went down , apparently North Atlantic ship wrecks are “not to blame” for drowning. Who knew?
There are, just the same, 2 genuinely useful messages in the new study's mix.
The first is that, despite the strange cottage industry that has sprung up to argue otherwise, calories count. In a reprise of the notorious “Twinkie diet,” the new study showed that some people with a very high intake of junk food were skinny, not fat. If total food and calorie intake are low relative to the body's metabolic demands for energy, the result is weight loss, not gain, no matter how bad or good the fuel in question. Conversely, studies have shown that overweight results when even high-quality fuel is over-consumed.
Calories count. But of course, so does the quality of food. The fallacy propagated by a noisome minority is that there is any need to choose between the two. In general, the higher the quality of one's food choices, the more readily one controls the quantity of calories it takes to feel full and satisfied. The more dubious one's food choices, the more one plays into the designs of Big Food to maximize the calories it takes to feel full, as so brilliantly chronicled for us all by Michael Moss. Quality and quantity both matter, and the best way to manage the latter is to attend to the former.
The second important message in the new study is that the BMI does not measure health. At the population level, there is a strong correlation between BMI and health outcomes, justifying the use of this rather crude measure in epidemiology. But heavy does not always mean unhealthy, any more than skinny means vital. The adverse health effects of junk food extend far beyond the BMI, and by not addressing that, the new study reminds us of it.
So, only in a world where tobacco is not to blame for emphysema, and shipwrecks in frigid waters not to blame for drowning, is junk food unimplicated in obesity. Junk food, per se, does not make us fat; as the new report suggests, overeating makes us fat. But junk food is engineered to make us overeat, and while that doesn't always work, it clearly works often. And even when junk food isn't making us fat, it can make us unhealthy in many other ways that are harder to see, until it's too late.
The truth, then, is simple: We, the people, would be much healthier, and many of us leaner, if junk were not a food group.
This, in turn, is part of a larger, and comparably simple truth: The fundamentals of healthy eating, and living, are clear, evidence-based, and consensus-based. But since this is obscured by a confederacy of fools and fanatics; by an analysis of parts that only serves to hide the whole; by seemingly erudite answers to misguided questions; by hyperbole and titillation; and by predatory profiteers, there is a need to shine a light on it. The truth here is simple, but alarmingly hard to see through a dense haze of business-as-usual.
As noted, two timely efforts are directing their high beams at these very shadows.
The first is a remarkable conference, sponsored by Oldways and taking place in Boston just over a week from now, devoted to mapping out the ground common to diverse experts in nutrition. I for one am highly confident there is room there for all of us, and I look forward to standing there with colleagues and singing a rousing chorus of Kumbaya. The second, a campaign rather than a conference, is the just-launched True Health Initiative. This effort, predicated on a genuinely intimidating mountain of evidence, and an unprecedented coalition of influential voices spanning the globe, is all about turning what experts know about healthy living into what everyone knows, and actually uses. Check us out, and if persuaded, please join us. For whatever it's worth, my wife already has.
So there you have it: Eat well, don't smoke, beware of haze, and look out for icebergs.
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.
Contact ACP Internist
Send comments to ACP Internist staff at email@example.com.
- Disabled parking and needless paperwork
- White coat vote
- Should he go to medical school?
- Lowering physician and patient satisfaction 1 clic...
- CAUTI SCHMAUTI! (part 3)
- Hear ye, hear ye, probiotics cure all!
- Lessons from a 1944 CIA manual
- Antimicrobial stewardship and C. difficile therapy...
- No kidding
- Go hard or go home
Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:
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, 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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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)
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,
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
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.
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.
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.
The Public Library of Science's open access materials include a blog.
One of the most popular anonymous blogs written by an emergency room physician.