The Science of Sugars: A Dietitians Perspective

Note: This was previously posted as a guest blog post on Healthy Blog Snack by former Foundation staffer Sarah Alligood

By: Sarah Alligood, MPH, RD   Date 1/5/09

Here at the International Food Information Council Foundation, one of the most common trends we see in nutrition is that consumers are confused about the sugars in their diets. All the time, we see people bombarded with messages about what they should or shouldn't eat, and the science behind those messages is often lost.

With that in mind, we recently teamed up with the International Life Sciences Institute (ILSI) to hold a Web cast, "From Science to Communication: Understanding Fructose, HFCS, and Sugars." The Web cast was designed to be for dietitians-by dietitians, to help clarify the confusion surrounding sugars that contain fructose.

It's a very scientific discussion for dietitians, but there are some important take-aways that can help put the issue of fructose-containing sugars into perspective for anyone.

The Science on Fructose
Fructose is a simple sugar found in many foods, including fruit, honey, and some vegetables. Studies have shown that large amounts of pure fructose should be avoided because of negative effects on triglyceride and blood lipid levels. But it is important to keep in mind that much of the research that has been conducted regarding fructose and health has used abnormally large amounts of pure fructose. These findings may not be applicable to the average person's diet because:

  1. Fructose is rarely consumed in its pure form-it most always occurs combined with glucose whether in an apple, table sugar, or in high fructose corn syrup (HFCS)
  2. The average fructose intake among Americans is 9% of total calories, much lower than the levels that have been studied

What about High Fructose Corn Syrup (HFCS)?
There have been many mixed messages about HFCS over the past couple of years, and much of the conflicting messaging has stemmed from a lack of distinction between pure fructose and HFCS. While study findings related to pure fructose have often been applied to HFCS, it is important to point out that they are not the same. Like table sugar, HFCS consists of two simple sugars - glucose and fructose. Table sugar is 50% glucose and 50% fructose. And of the two types of HFCS, one is 55% fructose/45% glucose and the other is 42% fructose/58% glucose. Adding to the issue is high fructose corn syrup's name. HFCS is actually not high in fructose at all, but it was named as such because it is high in fructose compared to regular corn syrup, which is composed mainly of glucose. Given how complicated this topic is, it's not surprising that some people are confused.

The Bottom Line
What it all boils down to for the consumer is that all added sugars-table sugar, concentrated juices, HFCS, honey, agave-contribute calories to the diet. Enjoying moderate amounts of any of these is not cause for alarm, but as with many ingredients, overdoing it can lead to excess calories and weight gain if not balanced. For more tips and tools on how to achieve a healthful, balanced diet and lifestyle, check out

Additional Resources:
The Truth About Sugars: 10 Facts You May Not Know
Fast Facts About HFCS