The human body needs this kind of dynamic stability, as do all other living things. The process is called homeostasis, in which internal conditions—like body temperature, blood levels of calcium, and blood pressure—are maintained within narrow ranges, despite the extreme changes that may occur outside.

But most of us today, in the name of convenience, are throwing out of balance the complex and overlapping mechanisms inside our bodies.

The human body settled on this pH range largely because our early diets consisted of a plant-to-animal ratio of close to 1:1, with fish and shellfish comprising much of the animal component. These diets, high in unprocessed plant fiber and fruits, would have been slightly alkaline, which guided our evolutionary development.

But times have changed, and so have our diets. Profound alterations in humankind’s cultural and biological environments, brought about around 10,000 years ago through the introduction of agriculture and animal husbandry, were then magnified with the arrival of the industrial revolution. On an evolutionary scale, such shifts occurred too recently and too swiftly for the human body to adapt. In conjunction with this growing discord between our ancient biology and today’s prevailing nutritional and cultural patterns, many of the so-called “diseases of civilization” have emerged—consequences of twenty-first-century diets meeting stone-age bodies.

The foods we consume today would have been unrecognizable to our hunter-gatherer ancestors and those first farmers, yet the nutritional needs of our cells have hardly changed at all. Meat products, dairy products, and cereals provide most of the calories in our diets, and they are all high on the scale of acid-producing foods.

But remember, our bodies lean toward the alkaline. So we’re making it difficult for our systems to maintain the acid/alkaline balance that has prevailed since the beginning of human time.

The basic rule is that meat and dairy foods have a high acid load, whereas vegetables and many fruits are acid-reducing. People frequently confuse the acidity of a food source with its acid load. It appears paradoxical, but a lemon—which is quite acidic—will actually reduce the body’s acid load once its mineral contents—generally found in the pulp—are absorbed into the body fluids. This is because the predominant minerals within the lemon have an alkalizing or acid-reducing effect on the body. They do this by forming mineral hydroxides and carbonates in our cells, which act like molecular sponges to “suck up” excess acidity.

In addition to eating more vegetables, you can also take potassium bicarbonate to help reduce your body’s acid burden. But why is it so important to reduce the acid burden of the body and move our diet back to match that of our evolutionary development? Two major risks arise from modern acid-producing diets:

Consequently, acid-producing diets can dramatically alter both bone structure and function. A high dietary acid load has been shown to both increase bone resorption—a process by which the bone structure is depleted—and decrease bone formation.

Recent studies have emerged that provide intriguing insight into the relationship between diet and cancer. Abnormalities in our acid/alkaline balance seem to play a major role in the beginnings of cancer by knee-capping the immune response and allowing cancerous growths to start. High levels of inflammation also block the body’s natural defenses by disarming its specialized white blood cells and enhancing the production of chemicalsignaling molecules to further inhibit immunity and encourage unchecked growth. Measuring the level of systemic inflammation can, in fact, predict a patient’s survival time for several cancers.