The Great Dietary Shift: What 10,000 Years of Agriculture Did to Our Body’s pH Balance

Our ancient ancestors ate a dramatically different diet from what we consume today. Thanks to groundbreaking research from the University of California, San Francisco, and recent comprehensive reviews published in 2024, we can now precisely quantify how different our ancestors’ diets promoted an alkaline balance in their bodies, whereas our modern diet promotes acidity. This shift represents one of the most fundamental changes in human nutrition since the advent of farming 10,000 years ago—and emerging research reveals its profound impact on multiple aspects of our health.

Measuring the Change

Researchers use several validated measures to quantify the amount of acid or base that different diets produce in the body. The most common method is Net Endogenous Acid Production (NEAP), but newer methods, including Potential Renal Acid Load (PRAL) and biomarkers such as urinary citrate and ammonium, are providing more precise clinical tools. A negative number indicates a base-producing (alkaline) diet, while a positive number indicates an acid-producing diet.

When analyzing ancestral diets, it’s essential to understand that our ancestors were primarily gatherers rather than hunters. Archaeological and anthropological evidence shows that gathered plant foods typically provided 60-80% of daily calories. The research findings are striking:

The average ancestral diet produced -88 mEq of acid per day (meaning it was base-producing)
A remarkable 87% of ancestral diet combinations were base-producing
There was considerable variation (±82 mEq/day), but most combinations remained firmly in base-producing territory

In contrast, the modern American diet produces +48 mEq of acid per day, validated by multiple real-world measurements. This isn’t just theoretical. Historical observations of New Guinean hunter-gatherers living a traditional lifestyle found that their urine pH typically ranged between 7.5 and 9.0, remarkably alkaline values that can only be achieved through a diet rich in potassium bicarbonate, a strongly base-producing substance.

Why This Dramatic Reversal Matters

The shift from -88 mEq/day (ancestral) to +48 mEq/day (modern) represents a swing of 136 mEq/day toward acid production. This reversal occurred through three significant dietary changes:

The displacement of base-rich plant foods that were the staples of our gathering-based ancestral diet
The introduction of cereal grains, which produce acid in our bodies
The addition of modern processed foods and high sodium chloride (table salt) intake, which independently drives acidosis

Recent research has revealed that chronic exposure to this acid load is associated with numerous health conditions:

Metabolic health: A high dietary acid load is strongly associated with insulin resistance, obesity (particularly abdominal obesity), and metabolic dysfunction-associated steatohepatitis (MASLD). Studies have shown that a higher acid load is correlated with increased triglycerides, a larger waist circumference, and a higher body fat percentage.
Cardiovascular disease: Multiple large-scale studies have identified increased risk of hypertension, cardiovascular mortality, and major adverse cardiovascular events in those with high dietary acid load. The association appears to be mediated through increased cortisol production, activation of the renin-angiotensin system, and chronic low-grade inflammation.
Kidney function: Perhaps most concerning is the impact on kidney health. High acid load accelerates kidney function decline, increases the risk of chronic kidney disease progression, and promotes kidney stone formation. The kidneys must work continuously to excrete excess acid, leading to increased ammonium production, which in turn causes inflammation and fibrosis.
Bone health: Chronic acid exposure forces the body to pull calcium from bones to neutralize acids, potentially contributing to osteoporosis and fracture risk, particularly in older adults.
Cancer risk: Emerging evidence suggests associations between high dietary acid load and increased risk of various cancers, including breast, colorectal, and lung cancer, possibly through effects on insulin-like growth factor-1 (IGF-1) and the tumor microenvironment.

The Mechanism: Understanding Metabolic Acidosis

Our bodies must maintain blood pH within an extremely narrow range (7.35-7.45) to sustain life. When we eat acid-forming foods, our bodies must work to neutralize that acid. While we can handle occasional acid loads, chronic exposure leads to a condition called “low-grade metabolic acidosis” or “eubicarbonatemic acidosis”—where the body maintains normal blood bicarbonate levels but at significant metabolic cost.

This constant acid neutralization:

Increases cortisol production
Activates inflammatory pathways
Impairs insulin signaling
Accelerates muscle protein breakdown
Compromises bone mineral density
Strains kidney function through increased ammoniagenesis

Making Better Choices: Practical Applications

While we can’t return entirely to a paleolithic diet, understanding acid-base balance can guide healthier food choices. Recent research provides specific guidance on food selection based on PRAL values:

Acid-Producing Foods (limit these):

Hard cheese (PRAL: +20/100g)
Meat and fish (PRAL: +8/100g)
Pasta and bread (PRAL: +6-8/100g)
Processed foods and soft drinks

Alkaline-Producing Foods (emphasize these):

Green leafy vegetables (PRAL: -10/100g)
Most fruits and vegetables (PRAL: -5/100g)
Potatoes (PRAL: -4/100g)

Dietary Patterns: The Mediterranean and DASH diets naturally produce lower acid loads, while typical Western and ketogenic diets tend to be highly acid-producing.

A Note of Balance

Interestingly, recent research suggests a U-shaped relationship between dietary acid load and mortality, meaning that extremely alkaline diets may also pose risks, potentially due to inadequate protein intake. The goal is not to eliminate all acid-producing foods but to achieve better balance, reflecting our species’ evolutionary heritage as gatherers who consumed predominantly plant foods supplemented with smaller amounts of animal protein.

Looking Forward

As research continues to reveal the health impacts of dietary acid load, we’re seeing the development of new clinical tools to assess and monitor acid-base status, including urinary citrate and ammonium measurements. These advances may soon enable personalized dietary recommendations tailored to individual acid-base status.

Understanding this acid-base relationship, along with our species’ historical reliance on gathered plant foods, can help us make more informed choices about the balance of foods we eat, potentially reducing our risk of chronic health conditions that may stem from this fundamental mismatch between our ancient biology and modern diet. As we eat, we potentially reduce our risk of chronic health conditions that may stem from this fundamental mismatch between our ancient biology and modern diet.

References:

The Great Dietary Shift: What 10,000 Years of Agriculture Did to Our Body’s pH Balance

Dr. Daniel Thomas, DO, MS