The Continued Fructose Debate

Some evidence indicates that natural fructose is not necessarily a public health concern, the more serious issues arise with concern to refined and highly processed forms which can be linked to a variety of metabolic issues like obesity, diabetes, fatty liver disease, and even some cancers. Fructose from natural food sources can be part of a healthy balanced diet, however, it is best to limit intake of refined and processed forms of fructose which includes high fructose corn syrup as a common food additive. Moreover, the main issue is that fructose is primarily consumed in modern societies via table sugar and HFCS, rather than natural sources. 

High fructose corn syrup is made by adding certain enzymes to corn starch which is basically pure glucose (another form of sugar), then this is used to create a syrup that contains varying amounts of fructose. Most varieties of HFCS contain either 42% or 55% fructose and 58% or 45% glucose, meaning that HFCS contains slightly more fructose than table sugar which typically contains 50% fructose and 50% glucose. Honey on the other hand, which is also a common food additive, is typically composed of a 1-to-1 ratio of fructose to glucose. 

Fructose binds to glucose to make sucrose/table sugar. The body can break down glucose, unlike fructose, but breaks down fructose more easily in this combination. Glucose triggers the release of insulin hormones that allows cells to use glucose for energy. Fructose does not trigger the release of hormones which includes leptin that tells the brain when a person is full, nor does it inhibit hormones that tell the body when a person is hungry, and as a result may contribute to overeating and weight gain. Foods containing glucose sugars have calories, and excess calories can lead to weight gain and health conditions. 

One can find evidence to support either side of the fructose debate making it difficult to separate nutritional facts from fiction. The undeniable facts are that the body metabolizes natural fruit sugar differently than processed or added sugars that have undergone refining during processing. Manufacturers tend to overuse refined and processed forms as additives which research has consistently linked to a higher risk of poor health conditions. 

Adding to the debate, this recent study from scientists at the University of Colorado Anschutz Medical Campus published in Philosophical Transactions of the Royal Society B Biological Sciences, suggests that fructose is a driving force behind the global obesity epidemic, officially calling fructose a “central conduit” of obesity and other metabolic related issues, suggesting it promotes weight gain, insulin resistance, elevates blood pressure, lowers active energy and damages mitochondria similar to animals ingesting large amounts in preparation for hibernation. 

“This is an in-depth review on a hypothesis that puts nature at the center of weight gain, examining how fructose works differently than other nutrients by lowering active energy,” says Richard Johnson, MD, professor at the University of Colorado School of Medicine and study lead author. “We determine a recently discovered function of fructose in survival that stores fuel in case resources become scarce. This is known as the ‘survival switch.’”

The researchers note that fructose is primarily consumed in modern Western society as table sugar and HFCS, which is different from the natural form of nutrition that was ingested by our ancestors ahead of the lean winter months. They posited that fructose works differently than other nutrients by lowering active energy, damaging mitochondria. 

“This work puts together in one place the full argument for how a particular carbohydrate, fructose, might have a central role in driving obesity and diabetes,” Prof. Johnson concludes. “This is a very exciting, new hypothesis that unites other hypotheses to point to the specific role fructose plays in the onset of obesity. And we can trace it back to our ancestors, as well as learn from hibernating animals, exactly how fructose causes this ‘switch’ within us.”

Before making any dramatic changes to your diet, consult with your doctor or certified dietitian to make sure that you are doing what is best for you.