Our distant ancestors who dined on a true Paleo diet had no control over how much sugar they consumed. Whatever amount occurred naturally in the wild plants they found while foraging or in the animals they corralled provided their daily intake by happenstance.

The first sugarcane cultivation probably began in New Guinea 10,000 years ago but sugar only came to be a European food ingredient in the 11^th Century. Then European powers established sugarcane plantations in the Americas in the 16^th Century and by the end of the 19^th Century sugar consumption had skyrocketed. According to Scientific American, this included a whopping 1,500 percent increase in England.

Today, sugar is added to most processed foods and I for one sprinkle it liberally on my Shredded Wheat. In fact, I find it improves the taste of whatever it’s added to except for iced tea, where it transforms a right dandy drink into a plum awful one.

But some say all this sweetness has a sour impact on our health. Pediatric endocrinologist Robert Lustig and journalists Gary Taubes and Mark Bittman have argued that sugar is a toxin that hampers our organs and disrupts hormones. They equate sugar with obesity, metabolic disorders, and cardiovascular disease. Taubes called it “uniquely toxic” and “the principal cause of the chronic diseases that are most likely to kill us.” He even equated sugar consumption with smoking, but for this to be true, even half a teaspoon per week would have to be detrimental since there is no amount of tobacco use that can be deemed safe.

There are different types of sugar, the best-known being the white granular table variety, sucrose. When alarming claims such as those in the previous sentence are made, the speakers are referring to the fructose form. That’s because the role of metabolizing fructose is handled almost entirely by the liver and eating exceptionally large amounts of fructose will tax the organ most responsible for exorcising toxins. Overburdening the liver produces uric acid, which leads to gout, kidney stones, and high blood pressure.

Bad stuff, indeed, and a good reason to limit the intake of fructose, but an insufficient reason to declare it the primary cause of disease. Dose matters. Concern about fructose is based primarily on studies in which persons consumed 300 milligrams a day, about five times what most persons ingest and equal to about eight sodas. Other studies involved subjects for whom high-fructose foods and drinks were almost the entire diet. Very few persons not being tested for this specifically would consume massive amounts of fructose while avoiding all glucose and other non-fructose forms of sugar, so this study has little bearing on reality.

There have also been rat studies that suggest fructose causes harm, but these are flawed for a different reason. Scientists have learned that rodents metabolize fructose in a vastly different way than humans do. Our livers convert less than one percent of consumed fructose into fats, while rats convert fructose into fat at a rate 50 times that.  So while the studies show that fructose consumption leads to clogged arteries, fatty livers, and insulin resistance in rats, it is not logical to conclude that humans would suffer the same fate for the occasional blueberry Pop-Tarts. 

In an interview with the Evolving Health Science blog, Dr. John Sievenpiper said, “A lot of this debate has been underpinned by the animal literature and ecological studies without recognizing the flaws and translating that information into real-world human scenarios. The problem has really been with someone like Lustig who can run through the pathways at very impressive clip and can convince someone that, OK, there’s so much biological plausibility, it must be true.”

But when Sievenpiper analyzed the effect of normal fructose consumption on humans, he learned there was none of the reason for worry the Sugar Kill Gang suggests. In his meta-analyses of dozens of studies on humans, he found typical fructose consumption resulted in no harmful effects on body weight, blood pressure, or uric acid production. Additionally, Archer Daniels Midland scientists collected data from more than 25,000 persons for seven years and found no connection between fructose consumption and levels of triglycerides, cholesterol, or uric acid. So moderate fructose consumption is fine. And one can safely ingest even higher levels of other sugars without any negative impact beyond spoiling tea.