The Greek physician Hippocrates, the “father” of Western medicine, allegedly wrote, “Let food be thy medicine and medicine be thy food” more than 2,500 years ago. I say allegedly, because it turns out that quote is nowhere to be found in any recovered documents ascribed to Hippocrates. Unfortunately, this oft-repeated phrase (I’ve invoked it myself) has created a few widespread misconceptions. One is that it’s possible to reject conventional medical treatment in favor of “curing” disease with food alone. Another is that if we develop a chronic illness, it’s because our diet wasn’t healthy enough. Those are big burdens to bear.
This doesn’t mean that nutrition doesn’t matter. It does. While treating illness did involve food in the Hippocratic era, food was not treated as medicine. Food was viewed as a substance that our bodies could assimilate after digestion, whereas medicine was viewed as a substance that could change the body’s own nature. As U.K. doctor and nutritionist Joshua Wolrich writes in his 2021 book “Food Isn’t Medicine,” drugs are able to do things to the human body that nothing else can, but the absence of a drug doesn’t cause disease. For example, he points out that taking vitamin C for scurvy works because scurvy is caused by a lack of vitamin C, but while antihypertensive drugs lower blood pressure, we don’t develop high blood pressure because we weren’t taking antihypertensive drugs to begin with. As he sums it up, “Food is food. Medicine is medicine. Let’s stop confusing the two.”
The limitations of nutrition
Generally speaking, getting adequate levels of necessary nutrients enables our bodies to develop and function normally. That means when improving diet quality or increasing physical activity, the biggest health gains happen when someone moves from a low baseline — nutrient deficiency and a sedentary life — to meeting the minimum recommended levels. Sure, there can be some benefit from going above and beyond “adequate,” but those benefits are proportionally small. That fact becomes lost in the rhetoric of “optimizing” our diets or “eating clean,” both of which are common in diet and wellness culture. At best, this drive to eat perfectly can lead to food obsession with no guarantee of the desired payoff (perfect health). At worst, it can lead to eating disorders or delay of appropriate health care. Our health care system is far from perfect, but accessible, quality health care does save lives.
There’s a lot of hand-wringing about poor-quality diets driving increases in many chronic diseases. Yes, there’s evidence that a nutritious diet that includes a lot of plant foods can help prevent cardiovascular disease and cancer — probably the two chronic diseases that we worry most about — but there’s no guarantee that eating healthfully will let you dodge those bullets. When I used to work with cancer patients, I had many conversations that started with the person sitting across from me telling me that they knew they “caused” their cancer by not eating “healthy enough.” You better believe I shut down that shame train.
Again, it’s not that nutrition doesn’t matter for health, but far too much emphasis is placed on personal responsibility, given that what determines our health is multifactorial. If you were to imagine these factors in a pie chart, social and economic factors accounts for about 40%, our genes/biology, physical environment and the quality of health care we receive account for about 10% each, and our personal health behaviors account for about 30%. And that 30% chunk? It includes nutrition as well as physical activity, sleep, stress, preventive health care, risky behaviors (unsafe sex, failure to wear seat belts), smoking status, and alcohol and drug use.
Where food matters more
It’s true that food has a therapeutic (dare I say medicinal) role for certain health conditions. Some are relatively rare and too complicated to explain here, but here a few common examples:
- Many people with irritable bowel syndrome can manage symptoms by avoiding certain high-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) foods.
- The only known treatment for celiac disease is total avoidance of gluten, one of the proteins in wheat, rye and barley — although there are some promising drug trials underway.
- For diagnosed food allergies or intolerances, avoidance of the offending food is key to avoiding unpleasant or potentially life-threatening symptoms.
- Avoiding certain foods (usually spicy, acidic or high in fat), especially in the evening, can help many people with acid reflux manage their symptoms.
In many more instances, food has therapeutic value, but only as part of an overall treatment plan. For example, if your occasional acid reflux becomes gastroesophageal reflux disease, you may need to avoid certain foods, leave adequate space between dinner and bedtime, and take medication. Similarly, while a heart-healthy diet, regular physical activity and stress management may help prevent or at least delay high blood pressure, if you’ve already developed high blood pressure, you will probably need to add medication to the mix.
It’s also worth noting that the food we eat can affect our day-to-day feelings of well-being, even where it’s not affecting our health, per se. For example, you might notice that eating Meal A for lunch leaves you satisfied and ready to tackle your afternoon activities, while eating Meal B makes you just want to crawl under your desk (or table) and take a nap.
The bottom line is that the best “medicine” is to aim for balance in our lives — with regards to food, movement, sleep, stress and substances — nurture social connections, have access to preventive health care, live in a safe and walkable neighborhood, and enjoy freedom from oppression. Some of those are easier to come by than others.