One of the questions I’m asked most regularly is: Is there an optimal diet for cancer?
I’ll give you the punchline at the beginning and then delve into the nuance: It is my strong opinion that thinking in terms of treating—or starving—cancer through diet is the wrong approach. Cancer cells are remarkably adaptive and will find ways to fuel themselves. To appreciate this, look no further than the cachexia sometimes seen in advanced cancer. The body wastes away even as the cancer continues to grow. It is not a pretty image, but it illustrates just how profoundly cancer can disrupt the metabolism of the body in service of its continued growth.
A better mindset is to eat a diet that nourishes you—and that includes (but is not limited to) the terrain of the body, the health and diversity of the gut microbiome, and the optimal functioning of the immune system. This aligns with a holistic philosophy of medicine in which we are less interested in treating disease in isolation and more interested in restoring health. From that perspective, the ideal diet will vary from person to person based on individual metabolism, genetic heritage, environment, and access to whole, nutrient-dense foods.
With that primer in place, we can get a little more granular and look at macronutrients—the three major categories of nutrients that comprise our food within the conventional Western nutritional paradigm: protein, fat, and carbohydrates.
Fat
There has been considerable emphasis in recent years on ketogenic diets as a means of altering metabolism in an anticancer direction. A metabolic approach to cancer does have some distinct benefits, but its therapeutic value rests primarily in addressing metabolism that is already impaired. I do not make the blanket assumption that deranged metabolism is the root cause of every cancer. To do so would ignore the environmental as well as the mental, emotional, and spiritual factors that feature prominently in my understanding of health and disease.
When it comes to dietary fat, my primary emphasis is on consuming healthy, minimally oxidized fats—fats that support the integrity of cell membranes rather than contributing to their damage.
Protein
I think of protein intake as more variable and dependent upon a person’s particular cancer diagnosis, physiology, and metabolic needs. Although I believe most people will thrive on a plant-heavy diet, neither a vegan nor vegetarian diet is a cure for cancer or a fail-safe means of preventing it. Human beings can live on entirely plant-based diets, but our physiology and anthropological history reflect our evolution as omnivores.
The amount and type of protein a person needs for optimal health may therefore differ considerably from one individual to another, particularly in the setting of cancer. For readers interested in exploring highly individualized approaches to protein and metabolic typing, I recommend consulting a physician familiar with The Gonzalez Protocol (opens in new tab).
Carbohydrates—or, Better Yet, Fiber
Image by ChatGPT, OpenAI
When it comes to carbohydrates, I would change the discussion rather significantly. Yes, a lower-carbohydrate approach can be useful for some people working to improve metabolic function. But I think we need to stop treating “carbohydrates” as though they constitute a single nutritional entity. The term is simply too broad. Instead, much of our attention should be directed toward fiber and the many benefits it provides, most notably for the gut microbiome.
A fiber rich diet is most supportive of health when we consume a wide variety of plants in a rainbow of colors, a proxy for a multitude of polyphenols and phytonutrients. These compounds nourish a diverse microbial ecosystem within the gut and exert beneficial downstream effects not only on metabolism but on all systems of the body.
Food, however, is more than a collection of calories and macronutrients. Every meal also delivers information to the body through micronutrients, phytochemicals, fatty acids, fibers, and microbial metabolites that influence gene expression, inflammation, immune signaling, and cellular repair. In that sense, nutrition matters profoundly in cancer, just not necessarily because we can use it to selectively deprive a tumor of fuel. Its greater power may lie in the biological instructions it continually provides to the terrain in which both healthy and malignant cells reside.
Nourish the Person, Not the Cancer
Ultimately, I don’t believe the most useful question is, What diet fights cancer? The better question is, What way of eating best supports the health of this person at this moment in time?
That distinction matters. When we make cancer the organizing principle of the diet, food can quickly become another battlefield—a collection of things to fear, restrict, manipulate, or employ as weapons against disease. But when we make health the organizing principle, the emphasis changes. We begin asking whether our food is nutrient-dense, whether it supports metabolic health, whether it nourishes the microbiome, whether it provides the raw materials needed for repair, and whether it helps the immune system to function optimally.
Cancer treatment necessarily asks a great deal of the body. Nutrition should not become a source of indecision. Its role, as I see it, is to help create the healthiest terrain possible in which healing, resilience, and recovery can take place.
