As our society advances, nearly all markers of human progress continue to improve, from literacy to infant mortality. One major exception is chronic disease, which has spread like a plague for the last hundred years.

10,000 years ago, just before the agricultural revolution, the main causes of death were accidents, food shortage, infections, and being eaten by predators. Chronic diseases like cancer, obesity, diabetes, and hypertension were rare to non-existent [1].

After the agricultural revolution, we moved into densely populated cities where the deadliest predators were not hungry lions, but invisible viruses and bacteria. In the last thousand years, there have been bacterial infections (plagues) that have wiped out 30-60% of entire continents and countries.

We look back at devastating plagues like the Black Death with horror, but also with a sense of assurance that plagues are a problem of the past. But this sense of assurance may be misplaced. While today's plagues, even in developed countries, are not as fast acting as the infectious diseases that wiped out populations, they're just as deadly, like slow moving tsunamis threatening to crush the foundations of our society.

Today, antibiotics and modern medicine have prevented most infectious disease related deaths in developed countries, but chronic diseases–like cancer, heart disease, and diabetes–have taken their place. Chronic disease is by far the leading cause of death in the US, accounting for 70% of lives lost [2].

6 in 10 Americans have a chronic disease such as cancer or diabetes, and 4 in 10 have multiple chronic diseases.

2 in 3 Americans are overweight, and 40% are obese. Half of Americans are expected to be obese by 2030 [3].

What kills us should drive us. Solving the top cause of death–chronic disease–should be one of our most important priorities as a society.

Instead, what drives us is killing us. 85% of chronic disease is caused by environmental factors like diet and lifestyle [4].

We’re driven to eat what’s tasty, affordable, and convenient instead of what’s nutritious, leading us to consume ultra-processed food developed by giant profit-driven food companies.

We work ourselves to death and decompress with Netflix and alcohol instead of movement and mindfulness.

The primary causes of chronic disease are poor nutrition, lack of physical activity, excessive alcohol, and tobacco use [5].

The answer to the chronic disease epidemic is not more pharmaceutical drugs and hospital care. Conventional medicine is not working. It is the wrong framework for preventing and reversing chronic disease, as Chris Kresser explains in Unconventional Medicine.

Conventional medicine was born out of the need for acute care. It works great for fixing a broken arm or prescribing antibiotics for an infection. But today’s chronic diseases require a lifetime of care, often across multiple doctors in multiple disciplines. However, most doctors still use a conventional framework of quickly writing a prescription instead of investigating the root cause of the disease.

Our healthcare system is reactive, not proactive. High cholesterol and high blood pressure don’t lead to an investigation of diet and lifestyle choices, but instead lead to prescription drugs, often taken for life.‍

Over half of adults in the US take prescription drugs, and 40% of the elderly take more than five medications [6].

As a result of this broken system that over-prescribes drugs and under-treats the causes of chronic disease, our healthcare costs have skyrocketed:

‍90% of healthcare costs in the US go toward treating chronic disease and mental health conditions [7].

The US spends more on healthcare than any other developed country. You would think all this healthcare spending would lead to better health outcomes, but the US ranks dead last among developed countries when it comes to overall care [8].

We need innovation, collaboration, and determination in chronic disease prevention and care. Instead, our best minds in healthcare are fixing symptoms and developing drugs instead of solving the root cause of disease. Our best minds in nutrition are arguing over fringe diets while most of the country still has McDonald's for breakfast and KFC for lunch.‍

As one example, Americans eat more sugar–a staggering 126 grams per person per day–than any country in the world, by about 23% [9]. The WHO recommendation for sugar intake is 5% of calories, or about 25-50 grams per day.

Sugar is one of the few foods that every diet agrees we should reduce, but instead of coming together over our similarities, we're pointing out our differences. Instead of shaming vegans or meat eaters, we should help those who can’t afford or aren’t educated enough to seek out real food, and move to change policies that make junk food so affordable.

If we want any shot at increasing our years of healthy, happy life, we have to do with food what we did with cigarettes. We need a national shift in attitude to reduce unhealthy behaviors and inspire healthy ones.

Sixty years ago, cigarette companies convinced us that smoking was cool, safe, and an expression of individual freedom. It took a while for that mainstream opinion to change–for most people to see cigarettes as the addictive, disease-causing products they are–and now that it has, smoking rates are lower than they’ve been in a century.

While ancient deadly plagues were spread by infection, cigarette sales were spread by social influence and clever marketing.

Like with cigarettes, today’s chronic diseases aren’t contagious, but their causes are still spread from person to person, and group to group, via influence and social pressure. Chronic diseases are caused by diet and lifestyle choices, and your choices affect the choices of others, of your colleagues, your siblings, your parents, your friends, and your children.

When children see their parents enjoying a Coke, ordering McDonald's, getting drunk, and never exercising, they take in those cues as the proper way of living. On the other hand, children who grow up eating healthy foods, skipping junk food, and staying active, are more likely to adopt those same lifestyle habits in their own lives.

For a while now, I've been the weird one at restaurants asking for my food to be cooked in olive oil, skipping dessert, declining another drink, and going home early to get enough sleep. Instead of being praised, I'm pressured. "C'mon, you only live once," they say, to which I respond, "You only die once, too."