Our genome has not changed in over 45,000 years, but the world has changed enormously and there are multiple mismatches with modern life. Homo sapiens evolved and thrived because we hunted down prey with the tools we made, ate a range of natural foods from the environment and led highly physical lives necessary for the proper functioning of our bodies and brains. Now, most of us spend most of our day sitting on our backsides, and more than 50% of our diet is made up of ultra-processed foods that hijack our brains' rewards systems while making us overweight and sick. Exposure to cold and heat caused our ancestors to upregulate critical stress response genes, which made us more resilient. Now, our thermoneutral environments are making us soft. We used to live in small tribal communities where everyone had a role and purpose. Now we are digitally connected and physically disconnected. Modern humans are the most overweight, depressed, medicated and addicted cohort of adults that has ever lived, yet life has never been so good! Backed by powerful research, Death by Comfort explores exactly what's wrong and what we need to do in order to survive and thrive in the modern world.