Sweets are loaded with sugar—that’s what makes them sweet. Everyone knows that. What isn’t as widely known is that other foods come packed with sugar, too. From snack foods to condiments, and from microwavable meals to breakfast bars, sugar has a presence in almost everything we consume. There was a time when sugar used to be a luxury reserved for only the wealthy and powerful, but it has since become ubiquitous, finding its way into so much of our food that it’s practically unavoidable. What brought us to this point of sugar saturation, and what does it mean for our bodies? This book aims to answer those questions.

Read on for several key insights from The Case Against Sugar.

Sugar has a long history that originates on the island of New Guinea. The natives there were the first to plant and harvest sugarcane.

Over time, the cultivation and harvesting of sugarcane spread to other regions and became popular. The problem was cost—harvesting sugar took too much time, money and energy. Further compounding the issue was the fact that sugarcane plants can only thrive in warm, tropical climates. Exporting the product added another expense that priced sugar out of the market. Consequently, sugar was unavailable to most people; they simply couldn’t afford it. Only the wealthiest people enjoyed this sweet commodity. In fact, it was so rare and valuable that it was even exchanged as a gift among royals.

But, as the saying goes, necessity is the mother of invention. The desire and demand for affordable sugar distribution spawned new methods of production.

While sugarcane is limited to warm, tropical climates, sugar beets are not. You can plant and harvest them practically anywhere. Once it was discovered that sugar beets could, if properly cultivated and harvested, produce sugar, the game changed for good. 

Technological advancements took sugar production to the next level, too. The invention of the steam engine—and the Industrial Revolution that followed—resulted in factories with exponentially increased output. By the early to mid-twentieth century, quantities of sugar that used to take years to produce could be churned out in the course of a single day.

Now that sugar was able to be mass produced by affordable methods, it was positioned to become a staple of the American diet. Previously, sugar consumption was limited to certain types of drinks and food, like coffee or tea. But after the Industrial Revolution, sugar found its way into all kinds of foods, and sweetened candies and ice cream became more popular and widely distributed. Sugar even became an ingredient in foods that had never previously contained it. For example, bread was being sweetened to improve its taste.

Of course, no story of sugar’s past would be complete without mention of Coca-Cola. This drink was invented just before the turn of the century, back in 1895. In the years that followed, the Coca-Cola formula evolved to include refined sugar, and soda—the sugary soft drink loved all over the world—was born.

We often count calories to prevent overeating and weight gain, but it’s not just the quantity of calories that matters—the quality matters, too. The assumption that all calories are equal is false—and for that reason, dangerous. With advances in nutritional science, we can no longer be excused for believing these old, disproven misconceptions.

Unfortunately, the sugar industry has, at times, taken advantage of popular misconceptions and touted their food products as being low in calories, despite containing high amounts of sugar. This has encouraged people to consume sugary foods without fearing weight gain or other negative health effects.

In the past few decades, critical discoveries have been made that have shed light on the differences between the calories we consume. We’ve learned that the body responds differently to foods that are high in carbohydrates or sugar. When we consume these foods, our blood sugar rises. When our blood sugar rises, a hormone called insulin is produced in greater amounts. And insulin—unlike most other hormones—does not burn or extract energy from fat cells. Rather, it causes more fat cell storage. When blood sugar levels rise, the body stores more fat, and it will continue to store more fat until blood sugar levels return to normal.

Ultimately, sugary foods and drinks cause weight gain. We don’t have to eliminate them entirely from our diets, but we should seriously limit them.

Despite popular misconceptions, obesity is not primarily caused by high calorie counts (although that is a factor). It is driven, instead, by the consumption of poor quality calories that result in more fat storage.

Since there’s big money to be made from sugar, there’s always been motivation to portray it in the best light. Back in 1928, the sugar industry began promoting sugar as a healthy part of a normal diet through an entity called the Sugar Institute. The goal was to increase consumer demand for sugar. Several marketing messages were included in this campaign, including the suggestion that sugar improves the immune system and revitalizes the body. These messages had a tremendous impact.

By the middle of the twentieth century, the American diet had changed dramatically and obesity rates were on the rise. It was also around this time that people began to believe—erroneously—that all calories were equal. With that belief in mind, why would anyone cut sugar from their diet? If calorie reduction became necessary, why not cut out the bad-tasting calories and keep the good-tasting ones?

In the 1960s, sugar substitutes hit the shelves and grew rapidly in popularity. This new competition was met with fierce opposition from the sugar industry. People wanted sugar substitutes because they were low in calories—diet sodas, for example, were consumed with the hope of shedding weight. The sugar industry countered this demand by making the case that artificial sweeteners containing saccharin and cyclamate were cancer-causing agents. On that basis, they lobbied to get these substances banned by the Food and Drug Administration. Millions were spent on this project, and the result was a ban on cyclamate; it was deemed unsafe for consumption. Notably, the amount of cyclamate that must be consumed in order for it to be dangerous is incredibly high, but the sugar industry succeeded in getting it removed from the marketplace.

Myths and rumors abound when it comes to nutrition and our health. One popular misconception is the idea that heart disease is directly tied to saturated fat consumption. This isn’t necessarily true, so why do so many people believe it?

As the rate of heart disease diagnoses increased in the twentieth century, the medical community was seeking answers. Ancel Keys, a scientist, suggested that heart disease was linked to the consumption of fatty foods. This theory gained acceptance because it seemed sensible. But if we delve a little deeper, we learn that Keys’ research was funded by the sugar industry. It also turns out that he was the creator of a sugary food packet called K-Rations, which was used by the U.S. military. In other words, he had a motive for making other foods look bad so sugar would look good by comparison. 

All through the 1970s and into the 1980s, fat was considered the real health danger linked to heart disease. Anyone who suggested sugar was the culprit faced ridicule from the sugar industry. However, evidence against sugar was mounting. As sugar consumption increased, health was deteriorating. Obesity, diabetes and high blood pressure were all on the rise. It became clear to many scientists that sugar was not some innocuous substance, but the primary source of all these major health problems. Concurrently, it was becoming clear that fat was not as bad as everybody thought. Having a high-fat diet did not necessarily mean one was unhealthy. Disease was being linked in increasing numbers not to fatty diets, but sugary diets.

Sugar consumption has been linked to a number of diseases, but none more clearly than diabetes. To understand why, consider what happens internally when you consume sugary foods or drinks. As explained earlier, the glucose in sugary foods and drinks causes blood sugar levels to rise. The body has to regulate this change, so the pancreas produces insulin. The purpose of the insulin production is to find a use for the glucose—it will either be burned for energy, or stored as fat for later. When sugar levels come back down, the stored fat can be used as an energy repository.

When a person develops insulin resistance, they end up with a problem. The glucose in their blood cannot be regulated. The body needs to produce more insulin to deal with the rising blood sugar by either burning it or storing it, but the insulin is no longer effective in that role.

It is now widely believed that sugar is to blame for insulin resistance. Studies have shown a direct correlation between sugar consumption and insulin resistance.

The inability of the body to deal with high blood sugar levels is not the only problem that stems from insulin resistance. Another problem is metabolic syndrome, which can lead to heart disease or diabetes. A symptom of metabolic syndrome is weight gain around the mid-section. The cause of it, however, is a perfect storm of obesity, high blood pressure and inflammation all affecting the body simultaneously. All of these issues are linked directly to the consumption of too much sugar.

A prime example of the disastrous effects of sugar can be found on the island of Tokelau, off the coast of New Zealand. A few years ago, a study was done that found the diabetes rate on this small island was off the charts—an astonishing 38 percent of the population had been diagnosed as diabetic. 

The sharp increase in diabetes diagnoses was a new problem, and it stemmed from a change in diet. Prior to the 1980s, the people of Tokelau had been eating a diet that consisted of fish, coconut, pork, chicken and breadfruit. Fat was a good portion of their diet (50 percent), while sugar was scarcely included at all (around 2 percent). A very small percentage of the people were diabetic. Among the men, only 3 percent were diabetic.

However, in the early 1980s, the people of Tokelau gained access to New Zealand’s mainland and their diet changed dramatically. Sugary foods were introduced to their diet and they began to suffer from weight gain, diabetes, and a host of other health issues they’d never experienced before. Their physical maladies proved the point that sugary calories were not just like other calories—they were extremely harmful.

Studies have also shown that people with insulin resistance (caused by too much sugar consumption) have a higher risk of developing cancer. Recent support for this link can be found in a study out of Scotland, where diabetics were treated with a drug that helped to regulate insulin levels and reduce resistance. The study showed that diabetics with insulin-regulating medication were much less like likely to develop cancer.

Sugar is hard to resist, but a healthy lifestyle demands that we limit our intake.