By Joy Bauer, M.S., R.D., C.D.N
In the 1970s, food manufacturers began replacing more and more of the regular white, granulated sugar in their products with corn syrup because it was substantially cheaper and extended shelf life. Shortly after this new, manmade sweetener exploded onto the scene, obesity rates started to climb at an alarming rate. After several decades of observing these concurrent upward trends, the logical question arose: Is the increasing amount of high fructose corn syrup in the US diet partly to blame for our country’s obesity epidemic?
To better understand this complicated and controversial topic, we’ll have to take a detour into the world of chemistry. (If you’d rather not drag up bad memories of high school science classes, you may want to skip to my bottom line at the end of the blog). In many ways, high fructose corn syrup is not all that different from the regular, white table sugar we add to coffee or homemade baked goods. Table sugar is made up of two different types of sugar–one molecule of glucose and one molecule of fructose–bound together to form a compound called sucrose. That means sucrose, or granulated table sugar, is exactly 50% fructose and 50% glucose.
The term "high fructose corn syrup" is a bit confusing, because corn syrup actually contains just about the same mix of sugar compounds as regular white sugar–the most widely used form of high fructose corn syrup is 55% fructose and 42% glucose. The only difference is that the fructose and glucose in corn syrup exist as separate compounds; they are not bound together to form sucrose. However, once the sucrose in table sugar hits our digestive tract, it’s rapidly broken down into separate glucose and fructose molecules, meaning our bodies most likely don’t recognize the difference between table sugar and high fructose corn syrup.
Short-term studies performed in humans suggest that the two sweeteners are metabolized the same way. For example, when researchers give individuals two different beverages sweetened with either sucrose or high fructose corn syrup and measure their blood sugar levels, hormone secretions, and appetite ratings in the hours immediately following ingestion, they see no differences in how the two sweeteners are processed.
But the research is ongoing, and questions remain concerning the relationship between corn syrup consumption and body weight over the long term. A Princeton University study published this year found that rats fed high fructose corn syrup for two months gained more weight than rats given sucrose, despite the fact that both groups consumed the same amount of total calories. Though it’s one of the few long-term studies looking at the impact of corn syrup consumption on body weight, this study is far from definitive. In fact, a nearly identical study published in 2009 by researchers at West Virginia University showed no difference in weight gain between sucrose-fed rats and corn syrup-fed rats.
For now, the general consensus among scientists and health experts is that high fructose corn syrup doesn’t increase risk of obesity any more than regular sugar. Rather, it seems that added sugars in general are contributing to our country’s weight problem. Both table sugar and corn syrup (and all other sweeteners, including honey, brown sugar, raw sugar, and agave) contain roughly the same amount of calories-about 60 calories per tablespoon. Regardless of their source–corn, sugar cane, brown rice, or honeycomb–sweeteners contribute lots of extra empty calories, and we don’t always account for these calories in our diet. The bulk of the high fructose corn syrup in the U.S. diet comes in the form of soda, other sweetened drinks, cookies, candy, and baked goods…all "junk foods" that offer little or no nutrition and gobs of calories. So, the biggest concern when it comes to weight gain probably isn’t the type of sugar, but the increasing amount of sugar we’re consuming.
If you’re looking for ways to trim added sugar in your diet, check out my recent blog "The Dangerous Side of Sugar". And don’t be fooled by companies that are switching over to cane sugar to make the claim that their products are "all natural" and better for you. Sodas, cookies, and candy made with regular sugar are no healthier than their corn syrupy cousins.
My Bottom Line: At this time, the majority of research does not support the idea that high fructose corn syrup promotes weight gain any more than other sweeteners (but like other sweeteners, it’s clearly not good for you). ALL added sugars are calorie-dense and, if consumed in excess, contribute to weight gain.
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