Why We Get Sick: The Hidden Epidemic at the Root of Most Chronic Disease—and How to Fight It: Summary & Key Insights

Insulin is often misunderstood as just the “diabetes hormone,” but it is far more fundamental. In my work as a physiologist, I’ve come to see insulin as a master regulator—a signal that dictates whether the body is in a state of storage or utilization. When you eat carbohydrates, they are broken down into glucose, raising blood sugar levels. In response, insulin is released from the pancreas to push that glucose into cells, where it can be stored or burned for energy. This is a beautiful system when it works properly.

However, in the modern world, insulin is seldom given a rest. Because we eat frequently—and because carbohydrate-heavy foods dominate our meals—insulin levels stay elevated all day long. Over time, our cells become less responsive to insulin’s message. The pancreas compensates by secreting even more insulin, leading to chronically high levels, even in people whose blood sugar tests may still appear “normal.” This persistent elevation is insulin resistance in action.

Insulin affects every tissue in the body: fat cells, muscle cells, the liver, the brain, and even blood vessels. When insulin resistance develops, all these systems begin to falter. Fat cells stop releasing stored energy efficiently. The liver continues producing glucose even when it shouldn’t. Muscles become less efficient at absorbing fuel. The brain loses its sensitivity to key appetite signals. The entire metabolic orchestra falls out of tune—and the consequences ripple through every aspect of health.

In earlier generations, our ancestors ate sparingly and moved often. Their meals were composed mostly of whole foods, and their days involved physical effort. Today, we eat frequently, snack constantly, and find ourselves bombarded by processed foods rich in sugars and refined grains. The human body has not evolved to handle this constant metabolic stimulation.

Every time we eat, insulin rises. The more carbohydrates—especially refined ones—we consume, the higher that rise. Our bodies, accustomed to occasional spikes, must now withstand constant surges. Add to this the effects of insufficient sleep, chronic stress, and sedentary behavior, and you have a perfect storm. Cortisol, the stress hormone, raises blood sugar and prompts more insulin release. Lack of sleep amplifies hunger hormones and dampens insulin sensitivity. Meanwhile, inactivity reduces the muscles’ ability to clear glucose, forcing insulin to work even harder.

In modern life, we are insulin resistant not because our bodies are broken, but because we ask them to do something they were never designed for—to endure perpetual abundance without reprieve. The result is a metabolic system stuck in storage mode, unable to switch into fuel-burning mode, steadily inching us toward disease.