What a sustainable diet means—for your patients and the planet

Timothy M. Smith , Contributing News Writer

Poor-quality diets are the No. 1 risk factor for premature deaths in the U.S. But diets rich in meats and processed foods aren’t just bad for personal health. They are bad for planetary health too.

Help Move Medicine

Medicine doesn’t stand still, and neither do we. AMA members don’t just keep up with medicine—they shape its future.

A podcast, “Sustainable Diets for Personal and Planetary Health,” explores the science behind dietary shifts that can promote better health for patients and the environment. It also highlights the unique role physicians play in advancing sustainable diets. Learn more about the  new Gaples Institute’s podcast series on nutrition for physicians.

Developed by the educational nonprofit Gaples Institute in Chicago, the podcast episode is the latest in a series that previews a more comprehensive, self-paced CME course, "Nutrition Science for Health and Longevity: What Every Physician Needs to Know."

“Clinicians have a personal stake in climate change, just like everyone else,” said AMA member Stephen Devries, MD, a preventive cardiologist and executive director of the Gaples Institute.

But unlike many other professionals, physicians have the potential to dramatically scale their impact, he noted.

“Each physician has an average of, say, a thousand patients in their panel,” Dr. Devries said. “Each of those patients—eating three meals a day—consumes about a thousand meals a year. … It turns out each physician has the potential to impact a million meals a year.”

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“We know from a health standpoint that replacing beef with plant sources of protein is associated with a whole host of health benefits, from reduced risk of diabetes to lower risk of cardiovascular disease,” Dr. Devries said.

But shifting from meat to plant-based protein also has environmental benefits, he said, noting that “the production of just one serving of red meat generates” 200 times the carbon dioxide (CO2) that is “involved in growing a serving of beans.”

Cattle digest fiber through a fermentation process that produces methane—an extraordinarily potent greenhouse gas—as a by-product, which they belch into the atmosphere. Methane is more than 50 times as damaging a greenhouse gas as CO2.

Meanwhile, dairy produces about 25% of the emissions of red meat. Fish generally has a lower carbon footprint, although it varies by species and how they're caught.

Greenhouse gases aren’t the only worrisome factor in food production. Water use is increasingly crucial as droughts become more common in food-producing areas, so crops too need to be evaluated for environmental impacts.

“Nuts have a really broad range of health benefits,” Dr. Devries said. “But the downside is that some nuts require a great deal of water to grow. Cashews, in particular, require the most. Almonds somewhat less. Walnuts, still less. And peanuts require the least amongst all nuts.”

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Physicians—and patients—who are not ready to go vegan can still make a difference. The EAT-Lancet Commission on Food, Planet, Health—a science-based global platform for food system transformation—recently issued recommendations for integrating the best available evidence on dietary patterns that support both personal and planetary health, Dr. Devries noted.

It identified a flexible, plant-heavy dietary plan that includes an upper limit for consumption of animal products. This includes up to—and at most:

  • One serving of dairy per day.
  • One small portion of red meat per week.
  • Two servings of chicken per week.
  • Two servings of fish per week.

“The most important step you can take is to talk to your patients about the dual benefit for personal and planetary health that good dietary choices can make,” Dr. Devries said.

Learn more in the 2022 update of the CME course “Nutrition Science for Health and Longevity: What Every Physician Needs to Know.” This enduring material is designated for a maximum 4 AMA PRA Category 1 Credit, and helps physicians begin an effective nutrition conversation with patients. The four-hour, self-paced course is developed and hosted by the Gaples Institute for Integrative Cardiology, an educational nonprofit focused on advancing the role of nutrition and lifestyle in health care.


This course includes four modules that are distributed in collaboration with the AMA Ed Hub, an online platform with high-quality CME/MOC from many trusted sources to support lifelong learning of physicians and other medical professionals.