Chapter 6. Food As Medicine

As we mentioned earlier, the path to optimal health and well-being is paved with plant-based whole foods.

These foods act like medicine to our bodies, creating an internal environment through which our overall health is allowed to thrive, and chronic diseases are not.

We’re sure you’ve heard these kinds of analogies before: put diesel in a petrol engine and the car won’t run; give candy to your cat and watch her get sick; feed Coca-Cola to a plant and see it die. Yet often, as intelligent as we are, we often pay less attention to our own health and well-being than to those of our car, cat, and even our house plants!

As far back as 400 B.C., Hippocrates wrote about the relationship of diet to health, but somehow these important lessons seem to have been lost or forgotten and, as a society, we’ve become more comfortable with taking prescription drugs than wholesome food as our medicine. Is this because vast profits can be made selling us unhealthy foods, and even more made when we need pills to tackle the ailments caused by those foods?

We do not have to make ourselves sick just so others can make money from us! We can step outside of this system by making different, healthier food choices. And, while we recognize that not everyone has the time or ability to cook, or access to fresh foods, almost all of us can make some changes, and many of us can make radically different choices. If we do this, the impact on our lives could be huge.

“What you eat every day is a far more powerful determinant of your health than your DNA or most of the nasty chemicals lurking in your environment.”

T. Colin Campbell


We may think of health as the absence of disease, but it is much more than that. Health is an active state in our body that is protected by our own built-in defense systems; defenses so powerful that they can actually reverse diseases, like heart disease, type-2 diabetes, and even cancer. It is the climate in which a flower might grow rather than wilt; an internal ecosystem that upholds life, rather than allowing it to collapse. It is not a destination, it is a journey we undertake every day.

Our body’s defense systems are closely connected to our diets, and while eating the right foods activates their abilities to keep us healthy, eating the wrong foods can destroy them entirely, making us highly susceptible to chronic illnesses.

Animal products and processed, high-fat, high-sugar, and high-sodium foods—all foods that a WFPB diet avoids—are the foods most detrimental to these defense systems. On the flip side, a wholesome plant-based diet strengthens our immune defenses because fruits, vegetables, and grains are packed with antioxidants that possess antiviral capabilities and can stimulate the activities of our immune cells.


It may come as a surprise that having a genetic predisposition to a certain disease does not mean that ill-health is an inevitability. On the contrary! In many cases, diseases are thought to run in families when really, it is the eating habits that cause those diseases that run in families.

Pioneering biochemist T. Colin Campbell found through over half a century of scientific analysis that animal protein in our diets causes cancer-promoting genes to “switch on”. However, a WFPB diet can limit and even completely “switch off” the expression of those same genes, thereby controlling disease development. These modifications to the DNA which regulate which genes are turned on or off are known as “epigenetic changes”.

The creation of hazardous environments (through a poor diet, exposure to stress, minimal sleep, and so on) have been linked to epigenetic changes seen in patients with cancer, depression, Alzheimer’s disease, diabetes, IBS, and a host of other serious health problems. Studies show that the positive epigenetic effect of eating a WFPB diet can be profound.

And then there is one more aspect that you may find interesting. Telomeres, which protect our DNA and have been found to shorten as we age, are also affected by what we eat, as well as other lifestyle choices. Smoking, eating a standard American diet, and drinking sugary sodas are three key activities that have been found to speed up telomere shortening and, subsequently, our body’s aging process. Conversely, a number of plant-based foods actually help to lengthen our telomeres and slow the aging process: foods like mushrooms, berries, spinach, oats, and flax.


We could go on all day about the amazing abilities of our body’s own defense systems and the incredible power of plants to reinforce those systems! Nevertheless, our resource list at the end of this guide will allow you to dig into those studies even further should you wish to.

For this chapter, we’ll simply end by saying that, regardless of how susceptible or invincible we might feel to illness, a lifetime of poor choices can lead us to chronic illness, even where we have no genetic predisposition to disease. The insidious nature of these slow-to-develop diseases means that they often begin in our youth but tend only to emerge as we approach middle age. That’s why, no matter how young we are or how protected we feel by our “good genes”, it’s never too early to ditch bad eating habits and start eating to live.

“Our genes are a predisposition, but our genes are not our fate. If they were, then you’d be a victim, but you’re not—you’re one of the most powerful people on the planet.”

Dean Ornish, M.D.

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