![the story of the human body: evolution, health, and disease prices the story of the human body: evolution, health, and disease prices](https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2021/nejm_2021.385.issue-8/nejmra2014530/20210816/images/img_medium/nejmra2014530_f1.jpeg)
Today, the average sugar intake in the U.S. Drinking soda all day - the contemporary equivalent - is a different story. Weight gain was not a real risk when our instincts meant we might scarf down the nutritional equivalent of a carrot whenever we happened to stumble across one. The invention of farming made starchy foods more abundant, but it wasn’t until very recently that technology made pure sugar bountiful." "Apart from honey, most of the foods our hunter-gatherer ancestors ate were no sweeter than a carrot. "For millions of years, our cravings and digestive systems were exquisitely balanced because sugar was rare," Lieberman wrote in an op-ed for The New York Times.
![the story of the human body: evolution, health, and disease prices the story of the human body: evolution, health, and disease prices](https://images.booksense.com/images/068/990/9780307990068.jpg)
The problem today is that humans have too much of the sweet stuff available to them. In other words, anything that made people more likely to eat sugar would also make them more likely to survive and pass along their genes.Īll the food challenges our prehistoric ancestors faced mean that biologically, we have trained ourselves to crave sweets. "Then they wouldn't eat enough sugar or have enough energy and wouldn't have children." "Imagine if someone hated sugar in the Paleolithic era," said Lieberman. This euphoric response makes sense from an evolutionary perspective, since our hunter-gatherer ancestors predisposed to "get hooked" on sugar probably had a better chance of survival (some scientists argue that sugar is an addictive drug). In the brain, sugar stimulates the "feel-good" chemical dopamine. The sweet taste was adaptive in other ways as well. This adaptation was a survival mechanism: Eat fructose and decrease the likelihood you will starve to death. "During that time," he said, "a mutation occurred" that increased the apelike creatures' sensitivity to fructose so that even small amounts were stored as fat. In a forthcoming paper, Johnson postulates that our earliest ancestors went through a period of significant starvation 15 million years ago in a time of global cooling.