Food causes but cannot cure cancer

Let us say that your hobby is rebuilding antique engines.  To clean metal parts, you use chemical solvents.  You apply the highly flammable liquids with rags.  As you work in the basement, you are careless and the rags pile up in an open plastic garbage can, overflowing onto the floor.  You love the smell it gives to the workshop.  One day a tiny, almost microscopic spark from a work light, lands in the rags.  Your house burns to the ground.

So it is with diet.  Many of us spend a lifetime eating high sugar, high fat, high salt and highly processed food.  Over years, this does immense damage to our bodies.  And then, one day, along comes a spark … a mutation occurs.  And then we have cancer.  Too late to clean up the basement workshop.  Almost as important, there is no way to put the fire by throwing on more oily rags.

Never does a day go by in the office, when a patient does not tell me about a state-of-the art low sugar, low fat, alkaline, organic-protein, vitamin-enhanced, kale-fortified, green algae colored, oriental tea flavored, super-diet, which is going to cure his cancer. Somehow, after decades of a saturated fat, glucose-infused, additive-poisoned, ultra-manufactured diet, combined with a sedentary, high stress, alcohol-soaked, tobacco-smoked life, from which has grown a mutating metastasizing neoplastic monster; a miraculous last minute Puritan-Hail-Mary-purge is the key to cure.

I try to be supportive, collegial and do my best to educate. I understand that such radical lifestyle changes are attempts to seize control in the face of a terrible threat. However, I must admit that I am frequently seized by the urge to scream, shout, rant and throw my stool across the exam room.  Therefore, here I go:

The diet that kills you is not the one you eat when you already have cancer.  The diet that kills you, like the rest of your lifestyle, is the one you have eaten for your entire life!  Not fair?  Perhaps, but absolutely true and anyone that tells you different is a charlatan and a fool.  Several facts make this as certain as tomorrow’s sunrise:

  1. Cancer comes from your own previously healthy cells. Breast cancer comes from normal breast cells.  Lung cancer?  Healthy lung tissue lining your pristine airways.  Leukemia?  You got the idea, perfect blood cells which become damaged.
  2. Most cancer occurs when something during your life, tobacco, radiation, chemicals (think the encyclopedic list of additives on that bag of flavored potato chips) or basic diet choices, damage and mutate mission critical genes in healthy cells.
  3. These genes are growth switches. Once these damaged genes no longer control growth, and cells start to grow, then it is too late. Stop smoking?  Too late.  Reduce your weight or start to exercise?  Years too late.  Start to eat the purest of foods, from the high pasture farms of Zen masters who meditate on the perfection of their product?  You are kidding. Too too late.
  4. Finally, and this is critical; Cancer starts from your own cells and the only real difference between normal cells and wildly growing malignant cells (cancer) is that their growth control gene(s) is turned on. This means that every cancer eats the same things you do. The same sugar.  The same fat. The same vitamins.  The same proteins.  You cannot kill a cancer by changing what you eat, unless you literally starve yourself to death.  Simply making your diet more perfect, will not kill the cancer. The harsh horrible reality is that it is too late.  And, sadly, occasionally, a more perfect diet may even help the cancer grow.

Does this mean you should continue to eat a lousy diet, just because you already have cancer?  Is it OK to continue to smoke?  Is it time to visit a nuclear waste site? Absolutely not.  It means that the goal of your improved diet is not to kill the cancer. 

The goal of an ideal lifestyle for a cancer patient is to give the body the best chance to fight the disease.  Reduce complications, tolerate therapy and heal. A comprehensive and complementary prescription for curing cancer combines things that make you strong, such as rest, exercise, stress moderation, social contact and proper diet, with medical techniques to directly destroy the neoplasm.  When the ship is sinking you need to both fix the hole and bail out the water.

Adequate hydration, lots of chicken and fish, nuts, red meat only three times a week, plenty of fruit and vegetables, no pharmaceutical grade manufactured ultra-dose vitamins, and limited alcohol.  Stay in touch with your body, it knows what it wants.  If it tastes bad, your body does not want it.  If you develop a craving, your body is broadcasting a need or deficiency.  The human body has been fighting disease for millions of years.  It knows better than you.  Listen.

While I am saddened by those whose lives of nutritional excess or disruption, release the demon of disease, I worry about the 80-year-old who completely changes a life-time pattern of eating, on the misconception that radical nutrition will stop the cancerous growth.   If she rapidly wastes, then wounds do not heal, complications will follow. I am infuriated by those that prey on the fear and guilt of sick patients with snake oil alternatives rapped in the labels of “natural”, “pure”, “organic”, justified by bizarre ideas of immunity, acid base metabolism or mega-dose nutrients.

However, I am encouraged and motivated by the strength of patients who work hard to fight, cure, rebuild and recover. I am in awe of those that with all their thoughts, might and soul, go into battle against cancer.  I am humbled by the ability and success of such warriors to regain healthy lives.


  • Ileana Balcu
    Thank you for this blog post! It considers the causes and describes why the diets won't work miraculously after a cancer diagnosis. It's respectful to everyone. It shows the importance of the patient knowing and caring for their own body. We need more of such blog posts written by MDs. It's time for conversation: honest, complete and insightful.
  • mimaedie
    This makes such perfect sense! I have known patients who have spent hours blending concoctions in the hopes of getting rid of the cancer.
  • cherie79
    Are you actually saying the cause of cancer is solely down to food or lifestyle ? I don't believe that, I have several friends with various cancers, none were overweight, smoked or lived on unhealthy diets. Lifestyle factors may well be a contributory factor as in smoking and stress. This sounds like blaming the victim, most smokers don't get lung cancer and I know quite a few people who developed cancer after a traumatic experience. Does anyone really know why the immune system fails to destroy rogue cells, I don't think so.
  • fightcrab
    cherie, the immune system cannot destroy cancer cells because they inactivate cytotoxic immune cells by several mechanisms. One of them is pd1/pd-l1. interaction.
  • When I got cancer (lymphoma) I was struck by how many people in my support group were otherwise extremely healthy people. The group included a dietitian, a wellness coach, nurses, a physician, a cancer researcher, a yoga instructor, several runners and many others who had extremely healthy lifestyles and great diets. None of us thought any specific diet would cure us although we all believed a healthy diet was important. Diet may be linked to colon and breast cancers and probably many other cancers, but the evidence does not support a significant link with blood cancers. I too felt a twinge of "blame the victim" in this post.
  • D Someya Reed
    It's so simple. You are not parent to your patients. They come to you for your advice and your skill. They do not come to be brow-beaten into following your every command. So simply say to your patients (those you believe are followers of charlatans), 'You came for my advice and my advice is I don't believe this plan is going to provide you with any benefit. However, it's never too late to start eating better (or start exercising, or stop smoking...or whatever it might be).' This way you've neither condoned nor condemned your patients. You've simply stated your stress, no fuss. And certainly no need to start throwing medical equipment around the room.
  • Carla
    I was very disheartened by this article and found it to be quite short-sighted. I firmly believe the answer to fighting cancer is in nature, and indeed in the food we eat. There are many credible studies out there about the benefits of certain compounds found in edible product to fight cancer, such as Curcumin, dandelion root, flaxseeds, mushrooms, garlic and all cruciferous vegetables, etc. We may not have found how to harvest the right dosage or combination of these compounds for the cure, but I believe food has the potential to cure cancer. After all, don't all medicines derive from some compound in nature? I know full well Paclitaxel derives from the Pacific Yew tree. We know aspirin comes from the bark of the willow tree, etc. I think counting purely on pharmaceutical drugs to fight cancer is short-sighted and to say food causes cancer, is even more so.
  • Anna
    Hi Dr Salwitz, I am just a little confused, do these foods cause the DNA to mutate? I thought it was a random occurence. What makes a carcinogen a carcinogen? What is the mechanism by which these substances make these mutations more likely? I would appreciate some information. Thank you.
  • Jo
    About a month after my husband passed away I was diagnosed with endometrial cancer. I had been over-eating and gaining weight every year for a number of years. I really felt that my weight had something to do with it. My oncologist explained to me that fat cells produce more estrogen and an over-production of estrogen can lead to mutation which causes the cells to keep growing leading to cancer. You can bet I suddenly got very serious about eating a lot better, less food and less sugar and food closer to nature. Now I am almost 3 months out from my hysterectomy and I am slipping back into eating things I shouldn't. I know exactly what Dr. Salwitz is talking about. I also noticed that most of the women in support groups I've seen for endometrial cancer are overweight or obese. Obesity is definitely a factor in this type of cancer.

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