High-fructose corn syrup (HFCS) is a type of artificial sugar made from corn syrup.
Many experts state that sugar and HFCS are key factors in today's obesity epidemic (, ).
HFCS and sugar are also linked to many other serious health issues, including diabetes and heart disease (, ).
Here are 6 reasons why high-fructose corn syrup is bad for your health.
The fructose in HFCS can cause health issues if eaten in excessive amounts.
Most starchy carbs, such as rice, are broken down into glucose, the basic form of carbs. However, table sugar and HFCS are 50% glucose and 50% fructose ().
Glucose is easily transported and utilized by every cell in your body. It's also the predominant fuel source for high-intensity exercise and various processes.
In contrast, the fructose from high fructose corn syrup or table sugar needs to be converted to fat or glycogen (stored carbs) by the liver before it can be used as fuel.
HFCS adds unnatural amounts of fructose to your diet, which the human body has not evolved to handle properly.
In fact, up until the last few decades, your diet would have contained only a very small amount of fructose from natural sources such as fruits and vegetables ().
In addition to lower concentrations of fructose, fruits contain fiber, water, micronutrients and antioxidants. None of the info in this article applies to whole fruit, which is very healthy ().
The adverse effects listed below are mostly caused by excess fructose, and these apply to both high-fructose corn syrup (55% fructose) and plain sugar (50% fructose).
Bottom Line: HFCS and sugar contain both fructose and glucose. Fructose is handled differently than glucose, and consuming too much fructose can lead to health problems.
High-fructose corn syrup is easily converted to fat when consumed in excess ().
This is because the fructose is metabolized in the liver. The liver can turn the fructose into glycogen (stored carbs), but it has limited storage capacity.
While smaller amounts of fructose from fruit can be fine, large doses from soda or sweets can overload the liver and be converted to fat.
In the long term, this fat accumulation can lead to serious health problems, such as fatty liver disease and type 2 diabetes (, ).
In one 3-week study, researchers found that the overconsumption of sugar and fructose led to a drastic 27% increase in liver fat ().
Other research has also found that fructose can increase fat gain to a greater extent than other calorie-matched meals ().
Remember, the detrimental effects of HFCS and fructose should not be confused with the fructose in fruit, which is healthy and safe in sensible amounts.
Bottom Line: High-fructose corn syrup can easily lead to excessive fat gain. This is because of its high fructose content, which is metabolized differently than other carbs.
Long-term studies also show that excessive quantities of sugar or HFCS may play a key role in obesity (, ).
In one study, healthy adult volunteers were given drinks containing either glucose or fructose.
When comparing the two groups, the fructose drink did not stimulate regions of the brain that control appetite to the same extent as the glucose drink ().
Fructose can also cause visceral fat accumulation. Visceral fat surrounds your organs and is the worst type of body fat. It's linked to health issues such as diabetes and heart disease (, ).
Moreover, the availability of HFCS and sugar has also increased average calorie intake, a key factor in weight gain. Research suggests people now consume over 500 calories per day from sugar, which may be 300% more than 50 years ago (, , 18).
Bottom Line: Research continues to highlight the role of high-fructose corn syrup and fructose in obesity. It can also add visceral fat, the harmful type of fat that surrounds your organs.
Excessive fructose or HFCS consumption can also lead to insulin resistance, a condition that can result in type 2 diabetes (, ).
In healthy individuals, insulin increases in response to the consumption of carbs, transporting them out of the bloodstream and into the cells.
However, the regular consumption of excess fructose can make your body resistant to insulin's effects ().
Eventually, this decreases the "flexibility" of your cells to metabolize carbs. Over the long term, both insulin levels and blood sugar go up.
In addition to diabetes, HFCS may also play a role in metabolic syndrome, which has been linked to many diseases, including heart disease and certain cancers ().
Bottom Line: High-fructose corn syrup can lead to insulin resistance and metabolic syndrome, which are both key contributors to type 2 diabetes and many other serious diseases.
Many serious diseases have been linked to the overconsumption of fructose.
HFCS and sugar have been shown to drive inflammation, which is associated with an increased risk of obesity, diabetes, heart disease and cancer.
The high insulin levels caused by sugar could also fuel tumor growth. Several long-term studies have found a link between HFCS intake and cancer risk (, , ).
In addition to inflammation, excess fructose may also increase harmful substances called advanced glycation end products (AGEs), which may harm your cells and make you age faster (, , ).
Lastly, there is also a greater risk of inflammatory diseases such as gout. This is due to the increased inflammation and uric acid production (, ).
Considering all of the health issues and diseases linked to HFCS and sugar, it may come as no surprise that studies are also starting to link them to an increased risk of heart disease and reduced life expectancy (, ).
Bottom Line: Excessive HFCS intake is linked to an increased risk of numerous diseases, including cancer and heart disease.
Like other added sugars, high fructose corn syrup is "empty" calories.
It contains plenty of calories, but absolutely no essential nutrients.
Eating HFCS will therefore decrease the total nutrient content of your diet. Because the more you eat of HFCS, the less room you have for nutrient-dense foods.
At the end of the day, avoiding high-fructose corn syrup may be one of the easiest and most effective ways for you to improve your health and lower your risk of disease.