Eating only whole, nutrient-dense foods is financially (and physically) out of reach for many.
Eating only whole, nutrient-dense foods is financially (and physically) out of reach for many. (Photo: Stephen Simpson/Getty)

Medicine, Not Healthy Food, Is Still the Best Medicine

Your diet impacts your health, but stop expecting so much from it

Eating only whole, nutrient-dense foods is financially (and physically) out of reach for many.
Stephen Simpson/Getty(Photo)
Christine Byrne is a journalist and soon-to-be registered dietitian.

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Late last year, Whole Foods CEO John Mackey went live on the Freakonomics podcast and claimed that Americans don’t need better access to health care. Instead, he said, “The best solution is not to need health care. The best solution is to change the way people eat, the way they live, the lifestyle and diet.” People weren’t happy. You can probably imagine why: Mackey’s chain is expensive as hell. Eating only whole, nutrient-dense foods is financially (and physically) out of reach for many. In 2020, 15 percent of Americans experienced food insecurity, meaning they were unable to afford enough food to live an active, healthy life.

But Mackey is far from the first to claim that certain lifestyle choices, particularly eating the “right” foods, can ward off or cure health problems. Dr. Oz, a controversial but popular medical doctor whose talk show reached over 20 million people last year, repeatedly touts things like “cancer-fighting superfoods.” He even wrote a bestselling book dedicated to the idea that “simple, healing, wholesome food” is a “remedy for everything from fatigue to stress to chronic pain,” according to the publisher’s summary. And the internet is rife with articles like “10 Amazing Disease Fighting Foods,” from WebMD, and “16 Foods to Cure Common Illnesses,” from the site Active.

At best, these claims blow small bits of evidence way out of proportion—sure, raisins contain nutrients that can contribute to healthy blood pressure, but eating them won’t magically cure hypertension. And at worst, the claims are pseudoscience. Yes, food contributes to health and plays a role in the prevention and management of certain diseases, but food isn’t medicine, and no diet can replace good health care. 

We Can’t Always Control Our Health

Mackey’s statement about diet and lifestyle substituting for health care is based on the wildly inaccurate assumption that our behaviors alone cause our health outcomes. Actually, health behaviors—eating, physical activity, smoking, alcohol and drug use, and sexual activity—are just one of many determinants and account for around 30 percent of a person’s overall health outcomes, according to a 1999 policy paper published in the Annals of the New York Academy of Sciences that’s often cited by health experts and policymakers. Genetics, the environment, and clinical care (which includes medicine) also contribute, but social and economic factors—income, education, social support, and the experience of racism and other stigma—are far and away the most significant factors, accounting for about 40 percent of a person’s health outcomes, according to the same research. 

“Food cannot disrupt the deep impacts of living in chronic poverty or disrupt the physical responses to microaggressions that many minorities face in their daily lives,” says Christyna Johnson, a Dallas-based dietitian. A 2007 paper published in American Psychology describes microaggressions as brief and commonplace indignities directed at people of color that the perpetrators are typically unaware of; examples include a white woman clutching her purse as a Black man approaches, or a store employee monitoring a customer of color more closely. Several studies, including a 2017 analysis in Social Science and Medicine and a 2019 study in Psychoneuroendocrinology, have found that experiencing racial discrimination raises a person’s risk of chronic disease. This likely has something to do with stress. “Racial differences in stress exposure (e.g., experiences of racial discrimination) … stimulate pro-inflammatory processes that may contribute to differential health outcomes,” wrote the authors of the 2019 study.

Johnson also used to believe that food could act as a person’s best medicine. “But through personal and professional experience, I’ve found this to be at best shortsighted and truly rooted in elitism,” she says. A millionaire CEO of a “healthy” chain telling people that they wouldn’t be so fixated on affordable health care if they would just eat nutritious food (that may or may not be accessible to them) perfectly illustrates Johnson’s point.

Maybe You’re Born with It

Social and economic factors aren’t the only health determinants that are somewhat out of an individual’s control. We all have unique genetic predispositions—some people are simply born more at risk for certain conditions, like heart disease, than others. Environmental factors also play a role. Sunlight, dust, chemicals, metal, plants, animals, and other things we’re exposed to daily can contribute to the onset of pretty much every illness, from kidney disease to infertility to skin cancer. And of course, disease can be random. A 2017 report in Science found that about two-thirds of cell mutations that lead to cancer are caused by random DNA replication errors, while only a third are caused by inherited genes, environmental factors, or behavior. (Although yes, some cancers are more directly linked to behavior; for example, smoking is the primary cause of lung cancer.) Even diseases that are more strongly linked to lifestyle, like type 2 diabetes and heart disease, can occur in people with no known lifestyle risk factors.

All of this disproves the notion that eating a certain way, or a certain food, can eliminate the need for health care and medicine. The fact that disease can (and almost certainly will) occur no matter what you do might be a tough pill to swallow. But Johnson explains that it can also bring relief in that you can stop blaming yourself for your health problems or micromanaging your eating habits in the name of disease prevention.

Nutrition Is Just One Tool

The point here isn’t to totally discredit nutrition. Of course a nutritious diet can positively impact your health! The Dietary Guidelines for Americans state that a healthy dietary pattern is associated with a lower risk of certain chronic diseases, including type 2 diabetes, heart disease, bone disease, breast cancer, and colorectal cancer. But they never claim that any dietary pattern alone, like Whole 30 or paleo, can prevent or cure disease. And they never mention superfoods, because these don’t exist—no one food has the power to make or break your health. “Food can be used to prevent onset of a disease up to a certain point,” Johnson says. But again, there are no guarantees because of all the factors at play.

As is the case with disease prevention, food plays a supporting role in the management of certain diseases. Medical nutrition therapy (MNT) is “the evidenced-based approach to treating medical conditions with food,” says Clara Nosek, a dietitian based in Modesto, California. Dietitians are trained in MNT, and there are myriad applications for the approach. In some cases, short-term dietary changes can treat an acute (short-lasting and sudden) condition; Nosek gives the example of reducing sodium intake to help reverse edema, which is swelling caused by excess fluid trapped in your body’s tissues. In other cases, long-term dietary changes can help someone manage a chronic (long-term and often lifelong) condition. Johnson points out that those with celiac disease must completely avoid gluten to prevent long-term intestinal damage and other negative side effects. Similarly, someone with diabetes might use diet as part of their strategy to manage blood sugar. Some uses of MNT are even more clinical, like feeding someone through a tube or an IV if they’re unable to consume enough by mouth.

Both MNT and a nutritious diet can help improve health outcomes, but neither is a replacement for health care. (In fact, MNT is typically provided by a dietitian, which means that it’s a form of health care.) The best way to catch and treat potential problems early on is by scheduling regular visits with your primary-care provider.

Literally speaking, food is not medicine. No matter what Dr. Oz might imply in this article, arugula doesn’t “fight” lung cancer and tahini won’t “boost” your immune system. In contrast, medicine does have the power to treat or cure health conditions. Insulin injections are vital in the management of type 1 diabetes, whereas dietary choices can only do so much. Chemotherapy and radiation can treat colon cancer by killing cancerous cells, but a high-fiber diet won’t do anything of the sort and may not even help with prevention. Fruits and vegetables won’t lower your risk of contracting an infectious disease like COVID-19, whereas vaccination will. Diet impacts health, but it isn’t nearly as powerful as medicine when it comes to treating disease.

Lead Photo: Stephen Simpson/Getty