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Knowledge of nutrition is power: What will you do with yours?

Dr. Neal Bernard recently wrote a JAMA Perspective that “Ignorance of Nutrition is No Longer Defensible.”1 He recounts clinical scenarios in which physicians failed to (accurately) convey dietary advice to patients, concluding with five action steps: nutrition-related continuing medical education, partnering with registered dieticians, EMR resources, convincing physicians to change the way they eat and systemic improvements in food availability. With the amount of commercial and public health messaging about healthy habits, it boggles the mind to think anyone, let alone a physician whose professional organization asks him to categorize the mere presence of large body size as a disease,2 could fail to have absorbed knowledge about nutrition.

When I completed my dissertation on the impacts of the Allied “hunger blockade” on foodways and public discourse in Germany around World War I3 and returned to medical school, I readily agreed with the common refrain that the formal nutrition curriculum was lacking. I repeated the line I had heard from an advisor that this was because dietetics had professionalized as a female science in the middle of the 20th century, while medicine remained largely male. Before the pharmaceutical revolution of the post-World War II era, practitioners had relatively few (efficacious) therapies to offer besides diet. But when I started seeing patients myself, I realized that physicians continue to have opinions about when, what and how much their patients eat.

Rather than a lack of education in nutrition, per se, Dr. Bernard is more accurately decrying the content of what is taught already, and perhaps how it is (or is not) put into practice. He notes that medical schools teach the deficiency model of qualitative, nutrient-based nutrition that has been the basis of mainstream dietary science since the 1920s. I would add that the clinical years bring with them further training in a diabetic diet of small, frequent, low- and/or complex-carb meals; the DASH diet for hypertension that is better than any drug we can prescribe; a salt- and fluid-restricted heart-failure diet; and renal-failure diets that moderate phosphorus, potassium, sodium and/or protein depending on the glomerular filtration rate.

General surgeons learn how to administer gut rest for bowel obstruction and advance diet as tolerated (ADAT). Plastic surgeons cite studies about the healing-promoting effects of protein, zinc and vitamin C. Intensivists debate early refeeding in acute pancreatitis and prolonged ICU stays, and surgeons are moving toward less stringent rules perioperatively. Today’s doctors can explain why a patient with celiac disease needs a gluten-free diet (and why it is unnecessary for someone without that condition); and pediatricians advise parents and children about age- and weight-appropriate intake and output at every well-child check and many acute sick visits, too. All of this is medical and practical knowledge about nutrition that doctors employ daily in myriad clinical contexts.

If Dr. Bernard’s team did not counsel the patient with a diabetic foot ulcer about his diet, that was a lost opportunity, but surely it was not because no one knew that diabetes was a dietary disease, a fact that has been common medical knowledge since the 19th century, when specialists recommended everything from oatmeal to vegetarianism to starvation keto diets.4 Perhaps the preference for action (amputation) over reflection (an honest conversation about eating habits) was an oversight back when residents still started their patients’ IVs, but no primary care provider I know practicing today would hesitate to offer an opinion about her patients’ dietary choices.

Now, whether the content of her counsel is any good is up for debate, but that she would offer it is unquestionable. Should pediatricians mention a child’s growth parameters in his or her hearing?5 Is the 150-year-old calculus of calories in/calories out really the most effective way to encourage someone to lose weight? Can a clinician, in good faith, recommend a plant-based diet – which Dr. Bernard and the Physicians Committee for Responsible Medicine prefer – to a patient who lives in an area with a low Healthy Food Index6 (aka a “food desert”)?

If I learned anything from my research on the history of nutrition, it is that there is no one right diet for everyone. For example, whereas the average early 20th-century German could do with a reduction in consumption of animal products, patients with tuberculosis were granted special rations of milk and butter to boost their immune systems during the war. Today, a patient with eosinophilic esophagitis or Inflammatory Bowel Disease cannot consume the volume of raw vegetables that a paleo or vegan eater might. Cystic fibrosis-related diabetes can be particularly tricky to treat, with the high-calorie requirement necessary to counter poor digestion sometimes clashing with the low-carb one. When promulgating “correct” eating messages such as “healthy” and “unhealthy” labels in the grocery store, we ignore “non-standard” eaters at the risk of confusion, exclusion and irrelevance.

Physicians are not ignorant of nutrition, so we should use our training and influence to recognize both individual shortcomings and address social determinants of health, as Dr. Bernard does with the Physicians Committee for Responsible Medicine. A diabetic without money for the electricity bill can store neither insulin nor fresh produce: We can educate about utility assistance programs and oppose privatization. A hungry child cannot learn: We can lobby for access to SNAP benefits and affordable school meals. Doctors can refer to registered dieticians with cultural humility about patients’ backgrounds and foodways,7 and they can ask hospital administrators to improve the healthfulness of food options for patients and employees alike. Knowledge of nutrition is power: What will you do with yours?


  1. Barnard ND. Ignorance of nutrition is no longer defensible [published online July 01 2019]. JAMA Intern Med. doi:10.1001/jamainternmed.2019.2273.

  2. American Medical Association House of Delegates. Recognition of obesity as a disease. H-440.842. 2013. The HOD vote contradicted the committee recommendation, which was that obesity not be considered a disease: Fryhofer SA. Is obesity a disease? AMA Council on Science and Public Health Report 3-A-13. 2013. Accessed August 3, 2019.

  3. Ehrenberger KA. The politics of the table: nutrition and the telescopic body in Saxon Germany, 1890-1935 [dissertation]. Urbana-Champaign: University of Illinois; 2014.

  4. Feudtner C, Bittersweet: diabetes, insulin, and the transformation of illness. Chapel Hill, NC: University of North Carolina Press; 2003.

  5. Freidenfelds L. The problem with fat-talk at the pediatrician’s office. Nursing Clio. 2016. Accessed August 4, 2019.

  6. Misiaaszek C, Buzogany S, and Freishtat H. Baltimore City’s food environment: 2018 report. Johns Hopkins Center for Livable Future. 2018. Accessed August 3, 2019.

  7. Aiken K. “White people food” is creating an unattainable picture of health. Huffington Post. 2018. Accessed August 3, 2019.

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