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Friday, April 27, 2012

Facts about the calorie shed excess heat, too little light

A calorie is, incontrovertibly, now and forever, a calorie. Well, a kilocalorie actually. Back to that in a minute.

Candle by kkalyan via Flickr and a Creative Commons licenseNot every gallon of gasoline poured into the tank of every car produces the same travel distance. But that does not induce us to ask: Is a gallon a gallon? Of course a gallon is a gallon; it is a precise and clearly defined unit of volume not up for debate. We recognize that variation in the fuel efficiency of cars can change what happens when a gallon of fuel is burned. But it was still a gallon of fuel.

A degree on any given temperature scale is a degree. That doesn't mean every degree will FEEL the same to you or me, because we are more sensitive to temperature change in some parts of the range than others. We are unlikely to notice the difference, for instance, between 41 degrees below zero Fahrenheit and 42 degrees below zero Fahrenheit. Both are so cold, who cares? But we might well notice the difference between 67 and 68 while sitting in an office if we happen to be a bit chilly at the former and comfortable at the latter. But still, a degree is a degree.

A mile is a mile. But walking one over flat ground when well-rested feels very different from climbing one up a mountain when exhausted. But the differences have to do with our condition, terrain and altitude, not distance. A mile is a mile.

Why, then, do we keep asking, as occurred in the New York Times, if a calorie is a calorie? Of course it is. It can be nothing else.

As noted above, the measure we actually use when talking about food is the kilocalorie. A kilocalorie (Europeans use the kilojoule, by the way) is the energy required to raise the temperature of one liter of water one degree Celsius at sea level. Does it sound as if that leaves much room for debate? It is a unit of energy, no more debatable than a unit of distance, temperature, volume or velocity.

Why, then, is there a cottage industry in questioning the calorie? And why am I so adamant that this cottage industry should be shut down? I will address these questions in turn.

Questioning the calorie sells. It sells books, articles, magazines, newspapers and air time. It exploits the difficulty so many of us have with weight control, and turns it into a dumbed-down pet theory, conspiracy theory, and/or magical thinking. It offers a false promise of weight loss independent of energy balance. And since real and keep-able promises about weight loss require the actual effort involved in dealing with energy balance, false promises perennially appeal.

My adamant opposition to this industry relates to the fact that it is harmful to health--public and personal. The more time we spend debating what should not be debatable, the more time we spend with understanding, consensus, collective effort and resources diverted from where they could make a meaningful and positive difference. The more often we buy a new answer to the "Is a calorie a calorie?" question, the more time we spend mired in epidemic obesity. Those profiting from the confusion probably don't mind, but you should.

"Is a calorie a calorie?" is the wrong question, obscuring all of the right questions and diverting our attention from what matters. It also is a classic example of creating confusion rather than alleviating it, by pretending to address a deep issue that is, in fact, profoundly trivial.

Here's what I mean: You are a little bit hungry, and on two successive days you get to eat limitless amounts of one of two foods with the same exact calorie content. One tastes absolutely great, and the other tastes absolutely horrible. Do you think you will eat exactly the same amount of both?

Eating more of a food that tastes great (as in: "Betcha' can't eat just one!") is NOT an invitation to question a basic law of physics. It's obvious to the point of truly trivial. Food made to taste really good will likely goad us into eating more calories. Duh.

Another non-controversy with which the constant questioning of calories makes hay: Two people can exercise the same, and eat the same, and one will gain weight while the other does not. Doesn't this prove that a calorie is not a calorie?

Of course it doesn't! All it proves is that I am not you, and you are not me! No one ever said that any two humans burn calories with exactly the same efficiency. As noted at the start, two cars may get very different gas mileage; that does not seem to tempt us to revisit the definition of a gallon over and over. People, similarly, differ in their fuel efficiency. Some can gain weight on very few calories. That isn't fair, of course, but no one ever promised us life would be. It is not a reason to debate the calorie.

The composition of food matters, because it can influence how many calories we are inclined to eat. We tend to eat more when food tastes better. We tend to eat more when food is energy-dense. We tend to eat more based on characteristics of everything from ambient lighting to dishware, as the brilliant work of Brian Wansink reveals.

We tend to eat less, i.e., fewer calories, when food is higher in volume and lower in energy density. We tend to eat fewer calories when food is rich in fiber content. We tend to fill up on fewer calories when foods have a high "satiety index" and properties that contribute to that include, but are not limited to: high quality protein, high water content and a low glycemic load. We tend to fill up faster on foods that are simple, close to nature and free of flavorings, additives and significant quantities of added sugar and/or salt.

In other words: Some foods are better for us than others, and one of the many virtues of better-for-us foods is that they tend to help us feel full on fewer calories. This probably seems obvious if you think about just a little. And that's exactly the point. The truth about calories is too obvious to support false promises, magical thinking, or book sales. So self-proclaimed renegade geniuses keep stepping into the limelight to rediscover the deep, dark debate about a basic unit of measurement that does not exist.

There are real challenges, and maybe even conspiracies, to deal with, and we are wasting our time and resources on pseudo-debate.

There is the fact that elements in the food industry have used brain scans to determine how to engineer foods that maximize the number of calories it takes for us to feel full. When they told us "Betcha' can't eat just one," it was a very safe bet they were placing.

There is the fact that our farm bill rewards all the wrong policies, and contributes to the low cost of high-fructose corn syrup and the high cost of produce.

There is the fact that experts in marketing are earning six- and seven-figure salaries to talk your 6-year-old into preferring foods likely to propel him or her toward obesity and the early onset of chronic disease, diabetes in particular.

And there is real and growing opportunity to use genomic advances to customize variations on the theme of healthful eating that lead to fullness, and weight control, most readily for different individuals.

You want a conspiracy theory? Maybe the frequency and popularity of the calorie debate is somehow being fueled by the elements in the military industrial establishment that profit from the status quo and don't want us to ask, and answer, truly meaningful questions. Or maybe it's just the work of those with books to sell.

Either way, we are wasting our time and precious resources. Imagine all the good that would come if instead of devoting our attention, time and money to improving the fuel efficiency of cars and finding better alternatives to fossil fuel, we devoted them instead to peddling books, articles, segments and blogs on the truly deep question: Is a gallon REALLY a gallon?

Folks, I have met enough people to know I am not unique. We have common sense in common. And our common, common sense is better than this! If it isn't, my daughter who lives in Brooklyn has told me there's a nice bridge for sale there.

We are wasting our energy debating the nature of the calorie, which is, simply, and incontrovertibly, a measure of energy.

And heat. The routine diversion of attention to a controversy about this that simply does not exist generates heat, but absolutely no light.

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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Blog log

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.

Auscultation
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 Richmond, Va., 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.

DrDialogue
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.

FutureDocs
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.

KevinMD
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).

Prescriptions
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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